Welcome to the forum.
An empty case held in the extractor should be able to dangle or nod slightly forward without falling free. Slight shaking back and forth should not dislodge it. It should not, however, be held in a death grip that keeps the case ridged. In other words, the hook bears against the case rim, but not hard enough to lock the case in position. The tip of the hook should not touch down in the extractor groove.
I don't know of a pounds force insertion spec, per se? You'd have to use a platform scale to measure that. Doing it by feel from experience requires you start with a good example to judge from. The only measuring tool I am aware of is a gauge Brownells sells which consists of a case-rim-diameter tab with a hole in the bottom for a trigger weight scale or a dangling weight (your choice) and it has a range of acceptable withdrawal weights in ounces that it should fall within when you pull it free of the extractor. Kuhnhausen does say that around 3 1/2 to 4 1/2 lbs of extractor pressure should bear against the rim of the case for hardball, but not to exceed 4 lb for light wadcutter loads. Unfortunately he neglects to illustrate how he sets up to measure this? I would say it takes half to three quarters of a pound or so pressure to push a round down out of a properly fitted extractor. Not a lot. The lighter end of the range assumes the extractor hook is fitted and polished inside and the brass is new and smooth.
I don't know what you mean by loose breech? If it is the gap between the barrel extension (hood) at the top back end of the barrel and the channel it rides in above the breech or recoil face, it is normal for those only to be tight with a fitted barrel for match accuracy that started with extra length in the hood for the gunsmith to file down to a fit. It is normal for them to have about 0.002" gap all around in the channel in the slide above the recoil face when you finish such a barrel. I've never seen that aspect of a fitting job truly wear out, though I suppose if you shot a gun a lot in sandy desert or other abrasive conditions, it would happen. The fellows living in the southwest could tell you. A GI barrel, on the other hand, can have a substantial gap there, as precision in the lock-up isn't needed to meet military accuracy specs.
I suggest you get a copies of Jerry Kuhnhausen's Shop Manuals on the 1911. They have the critical dimensions and inspection criteria all neatly laid out, and other than a couple of spots, like the measurement I just mentioned, is pretty clear.
