Optimal Carpenter skill path.

[CainaMalebolge]

I've spent some time working on this, and you need to look out for SE's dirty trick. Pile up lots of Walnut, Yew, and Oak logs. I'm currently trying to get 300-400 of each, just to be safe. If you follow this path you should be r50 without having to do all that much.

Item (Rank Synth)
Walnut Lumber (16)
Yew Lumber (21)
Oak Lumber (26)
Oak Mask (30)
Yew Mask (40)
Walnut Mask (45)

SE's dirty trick is the disparity between Walnut Lumber and Walnut Masks. I have a few people in my LS that wound up doing hundreds of synths for Walnut Lumber at r35+ for basically no SP. Making the lumber for the masks near/at the appropriate levels will help maximize your time, unless you want to do all those synths for no SP.