Sounds like a 4 to 5 inch tube is a pistol that fits you.
Keith routinely shot a 1911 at extended ranges.
Bullseye shooters must shoot with precision using the classic one hand stance 50 yards.
The method I use to determin my range limitation is as follows:
Place 8 inch paper plates at various ranges. I shoot each plate. My max effective range is the one that I can place each shot on the plate every time and each shot on the closer ranges.
I then obtain full size live animal archery targets and place them at the same known ranges. I practice until I can get a vital hit every time. before i go on the hunt I have a buddy place the targets at unknown ranges in a wooded area which simulates the terrain I will be hunting. I then walk the course and shoot each target.
Frankly, we can learn a lot from the techniques Archers use when shooting unknown distance targets.