I think your best bet is to look at the size of the shirt on the tag, ie: 15/35 meaning a 35” sleeve. Some shirts have extra fabric to account for several warm water washings and cycles in the dryer that might shrink it.
As for where you want your dress shirt to terminate on the cuff, I’d say after your wrist ends, but before the base knuckle on your thumb and just covering a bit of your palm’s bottom.
As for how wide you want your cuff, it’s probably more about personal preference. Some people prefer a tighter cuff on the wrist. I have about two fingers’ height above my wrist.