RE: full or modified barrel
You will be compromising with any ONE choke...For quail and rabbits an Improved Cylinder works best for most of the conditions you will encounter...
For doves, either Improved or Modified, depending on the setup...Squirrels running through the woods...Modified...Flattened out on a limb...Full....
Turkey chokes are usually XX-Full and as mentioned with steel shot, many chokes are bored Improved...