I would agree with George that finishing is probably best left until the
bowl is dry. If you must finish it straight away, a non curing finish
like mineral oil or beeswax might be a better compromise.

If you turn the bowl thin enough, it will warp rather than crack. Here
is a yellow birch bowl that I turned recently:
http://chipshop.blogspot.com/2005/04/warped-bowl.html
It is now dry and waiting for the base to be trued up before finishing.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com
http://groups.yahoo.com/group/toolrest/