First of all, what you see in the viewfinder are specks on the focus screen, mirror or trapped within the camera's pentaprism assembly itself and these HAVE NO RELATIONSHIP AT ALL with spots on your images. When you take a shot with a DSLR, the mirror flips up, covering and sealing off the focus screen and pentaprism above it before the shutter even opens to take the image by exposing the sensor to light.
There is some small risk that dust specks on the mirror or focus screen might eventually migrate around inside the camera and find their way onto the sensor. But this isn't very likely. It is also possible to have the mirror/focus screen cleaned, but I recommend you leave that to professionals because both these items are very easily damaged and you can end up with an expensive repair if cleaning is done incorrectly. Dust on them is just a minor nuisance anyway, for the large part.
IMO, it's utterly silly to be afraid of changing lenses, too. I do it all the time in quite dusty conditions...
I try to not change lenses under the worse conditions. I may move to a clearer area, make the change quickly, holding the camera face down, etc. And, yes, I'm usually shooting with at least two cameras, and that minimizes lens changes. And I use common sense. But I also don't hesitate to swap out a lens because of some "fear of dust".
It's not all that big a deal. Cameras can be cleaned. Plus modern digital cameras with self-cleaning sensors are pretty amazing. Dust has always been a minor issue for photographers, even with film! But even if dust gets on the sensor and ends up in an image, it's usually very easily retouched. Much easier with digital than it ever was with film!
Regarding cleaning... The Copperhill Method (wet cleaning) is good, but is only part of the process. It is typical to need to follow up a wet cleaning with a Sensor Pen to polish away some slight haze that the wet cleaning fluid inevitably leaves behind. Before and after that, it's common to need to use a bulb blower to puff away loose specks and/or a device such as a Speck Grabber to lift away any individual specks that find their way back onto the sensor.
The loupe you got may not have enough magnification. You may need to get stronger, or just use magnifying eyeglasses in conjunction with the loupe. Be aware that what you see in the image is upside down and backwards on the sensor... for example if you see a speck in the upper, lefthand corner of your image, when you go looing for it you'll find that speck is in the lower, righthand corner of the sensor.
But, even with great care you still may see some tiny specks remaining when you do a test shot at f22, f32. If enough, redo the wet cleaning, polishing and puffing... or use a dry method such as lightly adhesive strips (Dust Aid, etc.) and/or an anti-static brush (Arctic Butterfly, etc.). It is common for more than one method of cleaning or repeated cleanings to be needed.
Another solution... don't shoot at f22! Such a small aperture is going to detract from your image due to diffraction anyway, so keep to f8, f11, f16 at about the smallest. Any dust specks will be minimized or completely invisible at larger apertures.
Also stop evaluating your images at 100, 200% or larger! That's silly... with modern DSLRs it's like making a five or ten foot wide print and viewing it from 18" away. At that level of magnification, nothing looks very good and every tiny flaw will be visible... Stuff that's so tiny it really won't matter when you actually make a print in a more normal size or make a low resolution, smaller image to be shared and viewed online. It's fine to zoom in to high magnifications when retouching your images... just back off a bit and be less overly critical when evaluating the image for other things.
For more info about cleaning processes, I'd suggest you visit
www.cleaningdigitalcameras.com. Read all of it! This site is maintained by several very experienced camera repair techs (one of whom has literally "written the books" on many repair topics), is a very thorough discussion of the cleaning processes. It's also tied to the
www.micro-tools.com website, which is one of the key suppliers to the camera repair industry, where virtually all the cleaning tools and devices are available individually or in bulk.
Copperhill Images themselves also have a lot of good cleaning info on their site, though they tend to put the most emphasis on the specific tools and processes they offer.
EDIT: several VERY important warnings...
NEVER use common cotton swabs inside a camera. These shed tiny, tough, cotton fibers that can get into and jam up fine shutter and mirror mechanisms. That can mean an expensive repair!
NEVER use "canned air" inside a camera or anywhere near optics. The blast from canned air is too strong around delicate, high precision shutters and mirror mechanisms. It also can spray liquid propellants onto surfaces which especially can make a mess of optics of any type.
BE CERTAIN your camera battery is charged up before starting a cleaning and work efficiently to complete the work in a timely manner. Also be careful not to accidentally turn off the camera mid-cleaning. In most cameras holding the mirror up and the shutter open during cleaning uses power continuously. If the battery doesn't have enough power or the camera is accidentally turned off, the shutter can close onto any tool being used to clean the sensor, causing damage to the shutter or mirror. With most cameras, a full battery charge will give at least a half hour to complete the work, but I try to finish in 10, 15 minutes or less.
If at all uncertain about doing the cleaning yourself, take the camera to a shop that offers cleaning. This will usually cost about 1/4 or 1/3 what it would cost to buy the supplies and tools to do the cleaning yourself. So it would be basically the same cost to have 3 or 4 cleanings done professionally, or to buy the stuff to do it yourself. OTOH, it can be good to know how to do the cleanings yourself and have the necessary stuff on hand, in case it's ever needed in an emergency.