I'm curious what service you're using for these generations (I'm assuming a service as you need a decent PC and some knowledge to set up a local model)? I've ended up being gifted a NovelAI subscription (which I am friends with a few of the people working on that) and have some small understanding of how to tune them in now, not that I could really help with fine-tuning these things of yours.
I'm still using Dream (by WOMBO, whatever that is). It is free to use, although several of their features are behind a paywall. You can get their "Premium" subscription, which I think is something like 90 bucks or something for a year, but I don't have that. I've just been using the free version. I then edit them with a (really) old photo editing program. My photo editing skills are not particularly advanced, but to demonstrate, here is the oriignal of the picture with Daneera and her apparent daughter:
Yeah, the Dream AI is by my understanding way behind in terms of image generation, though from what I recall I was more concerned by their privacy policies the like 2 years ago or so when it was spreading around (like getting images of Hitler to sing to Queen songs). Of course, I can't speak for their UI but I know a majority are doing like Tevish and setting up Stable Diffusion versions to run on their GPUs. There's been a lot of developments in the last year that means the AIs are a lot less demanding (and a leak of the latest model so a decent chunk of people are using that through morally- and legally-grey avenues), though I'm not one to really talk to about requirements. I've even heard of this new thing called LORAs which are, like, really compressed training data.
I could maybe gift you a month of NovelAI for image generation if you're really interested in it.
Yeah, one of the nice things about the Stable Diffusion UI I work with is that I can set a random seed, or if I let it roll, it will tell me which seed was used for which image, so if I like one I can make variants on the same base canvass. The ability to do that was a big part of what I was looking for at first as I have ambitions to do a visual novel, and I need to be able to have the same character with multiple expressions, so having someone still look like a given person when I add "Smiling" or then change it to "Crying" or "Angry" is important. It's not been perfect, there are usually subtle changes in the details of their costume, but it is fairly good at that.
Yeah, my method with most of my experiments has been to try dialing in some details by adding one tag at a time, then when I get a pretty good composition, use that seed to start making smaller changes, like increasing or decreasing the influence of certain tags (as an example, "muscular" is a *very* strong tag and usually has to be reigned in). Also, if you're not aware, there was a gigantic project someone put together about how a large collection of nounds, adjectives, adverbs, etc. affect the image, so you might be able to find better tags with greater or lesser influence if it suits you.