Hi Hilmar. I've done this. I'm sure there are personal preferences, here's mine: I try to keep it close to a conventional 118* point. The thing about broken drill bits, the web gets thicker as the drill gets shorter. This will leave a flat spot on the bottom of the pocket you just spotted, gives your drill bit a chance to walk anyway. You should try to "thin the web" on your spot drill so it leaves a nice pocket, sharp cone on the bottom. There has been lots written about this subject, sorry I don't have anything more specific. Thinning the web is quite a trick, it can be done by hand, with practice, the hard part is finding a sharp enough corner on a grinding wheel to do it. Dremel disks may help if you can mount the tool solid and hold the drill bit in your hand. Good luck.
DB
