The Wolf thing is brilliant for drilling centres, but it was the metal dowel pins that would serve to accurately locate the start of the dowel hole in the other work piece, and to that measure answered the OP question.
Drilling it straight is an exercise I was leaving to the reader's technical skills although the wolf thing does help, as does drilling through a CD using the reflection to ensure verticality in multiple axes. I've always fancied one of those portable drill presses, but I've never really had the use for it.
I got mine with a job-lot of tools I bought at an auction - it's been used by me just 12 times . . . for 3 sets of 4 table legs!
