I used 3/8" glue down engineered wood in my prior MH. I had some pieces left from doing a few rooms in my house so I laid them out on the existing vinyl floor and ran the slide in and out a few times to check clearance.
It's a given that you can go at least as thick as your tile. You could lay some 1/4" plywood or paneling on top of the tile and run your slide in over it and see if it clears, if so try some 3/8", and so on. I believe I taped mine down and moved the slide a little at a time.
I'm sure there are several of us that will be interested in seeing how much you do and hearing about the install. I will say that it was very time consuming and I made what seemed like 10,000 cuts and consequently 10,000 trips in and out of the MH. I swore I'd never do it again, but that was then!!
Send me a PM if you'd like more info or pics.
Oh yeah, I read a lot of Ernie's posts before starting.
Alpine Coach........That's how Jaguar would've done it!