Some of the models are easy to pose no mater what clothing they are wearing or what scenery they are in. Others seem to be a real problem. The sliders stop working and you have to use the number system to position the model and pose limbs. So... the questions.

Does deleting the clothing as you undress the model make things easier as you go along rather than just hiding the clothing?

Do you adjust the model's body shape as you undress her? I'm particularly thinking of breasts here when the bra is removed.

Can you simulate loose clothing if a model is wearing it? Dresses and skirts particularly relevant in this one.

I never encountered the posing issue you are describing. Some of the curvier models have a lot of problems around where the thighs meet the rest of the body, but that's about it. 

I usually create a 3-frame animation. Frame 0 is no clothes on, frame 1 is underwear on, and frame 2 is everything on.  Ideally. Sometimes I need more, depending on the outfit.  Later I photoshop the frames together to get all the missing combinations.

 I  set the "visible in render" of clothes in each frame,  Clothes that are completely hidden under other clothes, are not visible in that frame.  No point dealing with collisions/pokethroughs from garments that can't even be seen. Ditto for the pubic hair.  Sometimes I completely hide them while I work, especially for simulations, but I never delete them.

Once that's done, I adjust facial expressions in the different poses to get some variety, and I kick off the render, telling it to render each animation frame as a series of images.

Once I am done, I can move to the next pose.  Move the camera and lights and re-pose the model all in frame 0 until she is perfect, adjust t do a couple test renders to make sure it looks good, then memorize her pose and restore it to the following frames.    If there are any dynamic clothes, I simulate them in the first frame where they are visible, though that's tricky enough to be its own topic right there. Sometimes you have to hide hair and other things it can get stuck on, or start the simulation from a more neutral pose to help keep the model inside the initial shape of the dress.

And yes always adjust those breasts.  I start from the natural naked pose, so I flatten the nipples and simulate whatever support they are getting from the clothing in frame 1. That usually means dialing the "natural breasts" value back down, and undoing most of the morphs I applied to make things hang realistically for the pose.

TY, there are certainly parts of that I'll be using. I think that some of the models are like 8.1 models and chew up memory. I have the same as you, 32gb, but my vid card is way behind and that maybe what's causing me issues. CPU  is an Intel i7-6700 quad core 4.0ghz, so it's no pentium... I'll keep experimenting and see if I can solve the issues and perhaps hold off on simulating clothes on the models until I have the other problem sorted.

Vivian is the only 8.1 model in the lineup, and she definitely caused me a lot of pain until I upgraded the RAM to 32gigs. She still takes longer to render than the 8.0 models, but at least things aren't freezing and crashing all the time anymore. I'm running everything on my fancy gaming laptop: it's fast but can't keep up with a comparable desktop.  Not sure 8.1 is terribly worth it over 8.0 to be honest. Especially since I have a lot of 8.0 models I already bought that haven't even been put to use yet. Then again it's kinda hard to stop the inevitable march of progress.