Hi, my own opinion (and guidance as mod) - it's usually best to post a single image (maybe 2) at a time. BTW, lemmynsfw does not have the concept of galleries/albums as on Reddit, so what you are doing is the only correct way to post more than a single image at a time. What I find that works well with most members is that "It's the quality, not the quantity" that usually matters. You can then do more posts of the same model by spaceing them out into different days.
See prior posts of Marika that I did here previously.
You can also spread out posts of same models to different relevant communities, such as !flatchested, !tinytitties, !skinnytail, !adorableporn, to name a few. Crossposting to other relevant comms is also a good thing to do, but try to again space them out over time, rather than crosspost the same image/post to all the other comms at the same time. Hope that helps.