Obviously the holes need to be perpendicular to the body or the ferrules wont line up, a drill press is the job for this.
Although, the first time I did ferrules i didn't have access to a press so i drilled plenty of holes in a piece of wood, found the 'squarest' one and used that hole as a guide for the string through holes. It worked fine but a press is much easier, faster and foolproof.
Hmm, since I don't have relatively easy access to a drill press, I may want to go the route of a Les Paul style tailpiece and bridge.
Something like this and this.
Hopefully once I strip the paint, I can fill the existing holes for the existing bridge with some wood putty.
I'll have to check this once I'm at home, but I don't think there is a truss rod inside the neck since it is so low cost. Does anyone have any recommendations on how to solve this? It appears to be a once piece maple neck.