I have; 2 MOA Venom, 6 MOA RMR, 8 MOA FF3, MRS - EPS Cary, MRS - 507Comp. I am also a geek.
I have run the same simple drills with the Venom and FF3 head to head under time. Drill was run 5 times each on a Ruger Mark IV on different days. I recorded the times to compare.
I did the same thing with the RMR and EPS Carry. I also tried every combination of the MRS on the EPS Carry. In this case the drills were done the same day with the dots mounted on two different Glocks.
Yes, there are other variables and the data sets could be larger. However the differences in average times were obvious.
I am very confident in saying bigger is faster when it comes to dots. My experiments confirmed the conventional wisdom.
The 507 Comp is new to me. I am still playing with the combinations. I may run the same experiment when the weather gets better. I have noticed hitting the head A Zone with the 2 MOA dot is doable. 2 MOA dot with 8 or 20 MOA circle get progressively harder as thing get bigger. The target area is obscured. Smaller is more precise.
6 MOA dedicated seems to be a good balance for a carry gun. That is what is on my G19.
2 MOA dot with 32 MOA circle is a good option also. That is what I am using on my G43X. If I were doing it over again, I would save $50 and go dedicated 6 MOA EPS Carry in place of the MRS.