30 is too high from what I've read and seen. 20 is the minimum dose to switch and that's pushing it.
Done right methadone can be not too difficult to get off, but it takes a LONG TIME (I know, I did it :-) )
But I'm hearing a lot of suboxone horror stories lately.
Thats a hard one to answer. I have never done the switch in that order. Common school of thought from people here would probably be a crapshoot. I am personally a little leery of the sub............too many conflicting ideas floating around. Our own SubDoc on the Expert Addiction Forum maintains that many should be on sub for life. I am uncomfortable with that one also. The withdrawals from methadone are long and slow. Same for the sub. Sub may have slightly less pronounced symptoms but you trade off for duration of withdrawals. I would suggest reading through the Health Pages still.........and you will get some more responses.