I give my straight oil/atf to people that ask for it (I have a small auto shop). One person asks that I put his in a 55 gallon drum and let it sit, then he takes all but the bottom 12 inches and I think all he does is filter it a lot.
Someone else takes the 5q jugs. They both have "hook ups" all over where they wander. Some take a bunch and I never see them again, they're just passing through
If you're getting into it, find small local shops either where you live or where you travel through. Many will gladly give it to you. If you don't know them well see if they'll have "your" drum out back with just oil and ATF. I am guessing that's what people do?
Waste oil removal costs shops money, even if they have a waste oil heater, when you're busy, you can't possibly burn all of it.
I do know it takes some space up to "process" it. You need storage, a way to move it, and a choice of filters, a series of filters, or some people use centrifuges (those don't work as well, as most oils have agents in them to keep things suspended)
I have IDI and TDI vehicles but I have been hesitant to try WMO, even cutting it with diesel or kerosene, simply because I can't afford new injection pumps if I damage any of them haha. It's tempting because I am often drowning in oil.
I am only familiar with Ford and older VW and even older MB running on WMO so if you end up going that route would be neat to see your set up