I use a Red Dot sight often when shooting a 600mm or 800mm lens because the FOV is so narrow that it is sometimes hard to acquire your subject quickly. Mine is switchable from red to blue to green with 3 different intensities of each so it works in almost any weather conditions.
I first rigged it up to mount in the hotshoe but quickly found out that was a bad idea as it made using the viewfinder very difficult. I then rigged it up on a Stroboframe flash bracket so it is directly above the viewfinder a few inches and that works a LOT better. It does help in subject acquisition, and I get a lot of funny looks when using it too.

I reviewed some of your portfolios and I saw many excellent photographs there and I have to admit that with your knowledge it surprised me that you are not thoroughly familiar with memory cards.
Cards are slow or fast and that obviously applies to both, CF and SD. If you buy a 32 Gb card for example with a rate of 4 you should not expect speed on downloading or in its performance. Here you have a card with lots of Gbs but limited in speed. On the other hand you could have a 32 Gb card rated 10 which is much faster and the manufacturer usually gives us the rate of speed at which the card reads and write in Gb and an isolated example would be a rate of 40 Gb/sec.
Please, understand that a card that has been labeled by the manufacturer as reading 40 Gb/sec. does not necessarily means that will be the same speed when writing to the card. It is usually slower than that but many times good enough to keep a good speed.
If you are into landscapes, snapshots, portraits or photographs of subjects that are static you do not need a fast card. A slower card could take a few more seconds to download but it will do the job and you will save money.
If you want speed, something necessary for fast downloads and action photography then you have to buy fast cards and you will have to do some research on them.
Each manufacturer has a way to say "speed" and it should not surprise you to find on some of this cards numbers like 400X or 600X.
Lexar, Kingston and SanDisk make excellent speed cards.

I just bought a SanDisk 64GB CF card (for my D800) on eBay but haven't used it yet. What I discovered while browsing eBay is that you pay more for speed a well as capacity. SanDisk sells a "SanDisk Extreme" and an "Extreme PRO." Download time for the PRO is advertised as 160MB/s and for the non-PRO, 120 MB/s. The price difference is $30-40.

The D800 (and its siblings) has slots for both SD and CF cards. I had already bought a 32GB SD card and I set the camera to store both JPG and RAW files. Bad idea. When I went to take the card out of the camera (to insert into the computer) it was stuck. I finally got it out and discovered the plastic housing was melted near the contacts. I filed down the melted plastic and found, to my relief, that the files were still intact and the card still worked. And, then I quickly decided to use the second slot for a CF card, for the RAW files. My Dell laptop has slots for both card types so now, everything is cool (literally).