1. I find all positions are better with loose joints. Posing for pictures not so good, but for sex, loose is better.
2. I hate banging a loose-jointed doll. I know a lot of people disagree but I don’t enjoy a loose-jointed doll near as much as tight joints. I like for her to be able to hold the position for the entire ride.
With loose joints, it is almost impossible to get her to stay the way you want her for the entire time.
Tight joints are good for photos and good for sex in my opinion from experience.
3. My favorite positions with dolls are cowgirl and face-to-face, all of which are much easier with a loose-jointed doll in my experience. Doggy is harder, but I have a couch to use so it isn’t a big deal.
So far a tight jointed doll only feels better to use sexually for oral and anything requiring standing, otherwise loose joints are my preference.
4. Loose joints are fine so long as the knees and elbows don’t hyper-extend. Though I much prefer stiff joints. Doing reverse cowgirl with a doll that has loose joints and hyper-extends is impossible.
I mostly do flat on belly from behind, doggy, and reverse cowgirl. The hardest thing about different positions is when the ass and pussy holes are way in the front of the doll. So proper ass and pussy placement on the doll really is the most important.