I think TRaSH serves as a good base. Their custom filters can be instantly imported using recyclarr and give you a general idea of how custom filters are meant to be used (which can be very overwhelming when you’re new to the ordeal) but sadly I disagree with TRaSH a lot on their group tiers for media formats. I think they make some mistakes placing some encoders as high as they do. (for example: micro encodes from PTer and BHDStudio shouldn’t be in the BluRay groups at all, as some of their releases are compressed harder than WEB releases from streaming services. I download BluRay encodes because I want it to be compressed to the point where it still looks identical to the BluRay it was sourced from.) Once you’re in the game long enough you just make up your own mind on what release groups should be prioritized over others.

As for your question regarding staying within the same file system, the answer is yes. Moving things over to the SSD does two things for you. 1) for every file you also need a duplicate on the SSD, not very efficient. 2) there’s not much to gain from this unless you’re expecting a large amount of simultaneous traffic. An HDD can carry about ~20 streams of 1080p content (as most releases are compressed to 8-10mbps) which is more than enough for most households.

I’d keep the SSD for seeding honestly, so that you can build up buffer on the trackers you’re on, but for most it’s still perfectly doable with HDDs only.