Call them - they will give you good guidance.
I personally like the use of a jig. I talked to them about that, and they said they just never used one, but if a straight crack could be beneficial. Lock n' Stitch uses a jig.
If you want a jig I would be happy to make one for you, just let me know.
They also said get as close to the freeze plug and stop - don't need to worry about the last little bit, just use sealer to keep from leaking.
