this is exactly the first saw I rehandled.
You'll have to be very carefully, when you
cut the slot for the blade because it is really thin.
Before rehandling I would cut some tests. The question is not if the saw is straight but if it cuts straight. (Wich is sometimes not the same thing.)
Sawmaker Tim Hoffman has now his own blog:
There you'll find his articles about blade and handle making, too.