I tend to agree. My research indicates that fowlers, muskets, and rifles were bored by the maker to accept a certain sized ball (based on the number of balls per pound of lead generally in whole numbers). Some makers opened up the bore to provide "windage" of about 0.010". Other made at the purchasers request a "high bore" with no windage resulting in a ball that had to be pushed down the barrel with no patching what so ever or as a "low bore" where the ball would freely roll down the barrel t the breach. I've come to the conclusion that we today put a lot of our preferences on to those of the past that they didn't have. Rifles, fowlers, muskets, and trade guns today have bores that are not historically accurate in any way other than being round since we shoot balls made to specific even diameters e.g. .500, .450, .600, .455 none of which correspond to the balls used during the time. Our need for tight fitting balls and patches to achieve the groups we consider acceptable appear to be far tighter than even the capabilities of the barrels of the time.
Loading I suspect was a product of the immediate need as you say. When hunting, enough patching to improve the odds of hitting the deer was important. When defending yourself, speed was all that counted. If the other guy was dodging your balls he couldn't shoot back and if you're lucky you might even get a hit.
As for the short starter, it had to have been invented and used to some benefit during the 18th C. otherwise in 1800 it would not have surfaced in documentation.