We have several washburns in the house (an elec and an acoustic) and now have an oscar schmidt OE30 in red, like new.

I've been fiddling with bass and wanted to try my hand at guitar and the acoustic is fine but I want to 'make more noise' LOL. My daughter has a very thin necked strat that my fingers don't like and my son gives me dirty looks when I play his, even though he plays my bass more than I do!

So picked it up, like new condition. Not a mark on it, pots are clean, sounds pretty good.
But the fret ends could use a bit of sanding maybe and intonation is way off but I'll fix that when I change the strings.

Strings are way too light for my liking - what are some good strings for a hollowbody?
Seems I keep seeing cleartone or snake oil as suggestions, 11 or 12s even, in nickel. I've been playing bass and learning on an acoustic so heavier is 'normal' for me and it's gonna be a while before I bend strings.

Haven't had a chance to play with it much - picked it up and friday night is a run all over the place with the kids and i work tomorrow. So I don't know how the pups will really sound but think I want P90s. Figure pups is where they scrimped to keep the price low.
How obnoxious is it to change pups on a hollow body?
Your guitar is routed for standard humbucking pickups, so installing a real P90 is not a good idea. You would end up with ill-fitting pickups. Some makers make "P90" pickups in standard humbucker size. This month's edition of Premier Guitar has an article on them. These would work fine.

Changing pickups on a semi-solid like your OE30 (yours is not a complete hollow body guitar) is a royal pain, because there is not rear cavity through which to work. You have to remove the pots through the "F-Holes" on the top, do your wiring, and then re-install them. Obviously, it can be done, but it is a pain.

If you want heavy strings, there are plenty of choices. Try DR Tite Fits at .13 to .56. That should be plenty heavy for you.
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