How are freestanding tub drains supposed to be connected?

[earlhouse]

Hi All.. I'm installing a freestanding tub on my second floor. Once I set the tub I won't have access to the drain. I was thinking silicone on the brass pipe that's going from the tub into the PVC drain. It'll sleeve into the PVC. But then if I ever want to, or need to pull the tub I'll have to yank and break the drain to get it apart.
How are these freestanding tub drains supposed to be connected?

 

[earlhouse]

Too late for pics. New tiles are in place. I have a 6 inch square opening for the drain. The PVC plumbing is done, P-trap included. I didn't think about access options until now, when we're ready to place the tub. Bro-in-law is putting motor down today. We'll probably set the tub on Sunday. I think I'm out of options other than either something like pipe glue or silicone.
I saw this thing online called a rough-in. It looks like a funnel with an opening at the bottom just large enough for the tub drain line to fit through, tight fit I assume. From what I read in the replies to my question, these aren't well known. So I'm not going to guinea pig it.
Thanks to all for you're replies.