I learned to shoot fast and precisely with a 45 degree mounted RDS with very little practice.
A nifty trick if you want an illuminated sighting point that can be viewed through a non illuminated scope that can be easily removed when not needed, is to mount a micro red dot out in front of the scope on a riser. Get it just high enough that you can see the dot on the target easily, sight in the red dot, ignoring the scope reticle. It works with every scope I have tried. A very simple install if you have a picatinny rail out in front of the scope. Not so easy if you don't. QD mounts are ideal. You can also remove the scope, leaving the red dot as desired.
You can even mount two red dots, a larger view Aimpoint style at the rear and a micro in front and have two precise illuminated aiming points for close range and long range.