Thanks for the responses folks, it looks like my thought process was sound.
I'm looking at working with a Civic in the near term, and while I am a thin guy, I think I want some more room to breathe under there. On my wife's Outback, the extra height probably isn't necessary. My next car probably won't have any better clearance than the Civic either.
I have a two-car garage to work in with a solid and fairly level concrete floor, so as long as the ramps/stands work, I should be in good shape. I've read about "safety checking" stands by shaking the car before getting under, and I'll plan to do that if I am ever spending time under it. In the near term, I'll need the stands for rotating tires and brakes if I can get the confidence to try it. My biggest issue is that I really don't have anyone to check my work or help me out if I run into something abnormal. My wife's sister's husband is a skilled DIY guy, but he barely has time to do his own stuff, let alone come over and babysit me.
About a year ago there was a DIY garage that opened up near my house, and my plan was to go there to try my hand at things. The shop had lifts, tools for rental, and a mechanic to hire for advice or to hand the project over to if you went past your skill level. Unfortunately they closed before I got over there, apparently due to insurance issues. I've also looked into finding any sort of auto maintenance class, either put on by the local adult education or at the community college, but unless you are going for a degree and can attend class at 11AM on a Tuesday, I've so far found nothing. So start with fluid changes and tire rotations for now and go from there.