If a ROM file works with SheepShaver and the installed MacOS system, it is OK, there is no need to replace it. That does not change with Snow Leopard.
"try and find it" cursor
What do you mean with that? Do you still use the May 2006 snapshot from Gwenole Beauchesne's site? Many bugs have been solved in the past years, also the cursor problems. I do not know which "new SS build" you are referring to. From earlier postings I got the impression that you are using the July 21, 2008 build, which should still be fine, especially the "H" version. If you use an older version, you can replace it with a newer one, like this one:
Or the one posted here, which contains the latest changes:
http://www.emaculation.com/forum/viewto ... 0713#30713
So far, the existing SheepShaver builds have been reported to run in Snow Leopard, so there should not be a reason to update SheepShaver for Snow Leopard. But we can not be 100% certain it will run OK on the release version until it is available and SheepShaver can be tested on it.