I understand that it is adjusted to each stock. My question is does it have to be adjusted twice for each stock? Once for the heel and sides and again for the toe?
Yes, the comb line (heel) and the belly line (toe) need to be adjusted and ground separately. This is much easier to do than to explain. Once the comb line is set about 2/3rds to 3/4s of the pad from the heel down is ground. I usually will use an 80 grit belt to rough grind and then finish off with a 120 and final polish with a 320 grit. Only then I will I change the pitch of the jig to grind the toe angle the same way. Doing it this way allows me to feather in the finish between top and bottom. Works like a charm.
I have used the same jig for decades. The only thing I had to replace was the screws and I modified the pad bar with some extra tapped holes to accomodate different hole spacing on some pads.
Short of grinding in and block sanding a new pad on a stock that is being refinished I found this jig is the easiest to use for consistant results. The added bonus is that there is zero chance of ever damaging a finished stock as all the grinding is done off the stock. As with any tool practise makes perfect. If you are a hands on guy excellent results can be had the first time. Practise will speed up the process once you are comfortable using it. I highly recommend it. I believe the name in Brownells' is J& G Pad Grinding Jig or something close to that.