Acoustic Guitar Construction

Before I do something in my ignorance, I have four rosewood fingerboards I'd like to trim to thickness before I do any other shaping/sawing on them. They are rough cut, 5/16" thick. I'd like to level and smooth them down to a 'fat' 1/4". My friend with the wood shop has a planer/joiner and a thickness planer. Am I fixing to ruin these fingerboards by trying to run them through the planers? I have a knockoff Safe-t-planer and a sanding drum I can get my drill press to turn, if either of these is preferable to power planing.

Thanks very much.

With a planer there is always the chance of "sniping" the first couple of inches then you have to get rid of that by sanding. Also, if you you run it through and not have the proper grain orientation there is a good possibilty of tearing up the surface (chip out). So, the situation can be like trimming a table leg -- and ending up with boards that are too thin. When only removing .062 or so we use our sanding machines -- reading the post on the "Safety Planer" -- seems you could make a mess with that as well.

Like the quote (I think from Kipling), 'softee, softee, catchee monkey'. Going very slowly and being very observant is probably a dandy idea. Might even learn something.
Thanks!

Since I started making my FB from blanks, I run mine through my Safe-T-Planer and haven't had a single issue. That's been about 20 boards.