Greetings Ironworker, If you haven't solved your timing issue yet, here's some tips and a manual that may help.
First, there are several things (many of which are very common place, but it's still good to mention) to check to make sure you're not having a basic problem. Make sure the needle is new (and the correct system is used), and fastened straight (not off-angle because of the round shaft). Because of the high speed these machines move at, everything has to be in perfect sync and if something is slightly off it will throw some stitches out. The correct needle system is 16x231 (or16x95, 16x257, DBx1, 287 WH, SY 2270) if you're using the wrong needle system it may not reach down quite far enough, etc.
Also, make sure it's cleaned properly, make sure there's no lint under the needle plate, in the tension apparatus, or inside the shuttle area that spins around the bobbin.
A manual that will work for you to adjust the machine is here http://parts.singerco.com/IPinstManuals/96-80_100.pdf It's for 96-80, 100 and others but the mechanics are the same and these instructions will match your machine. Also, look to the parent site http://parts.singerco.com/IPinstManuals/ for a more extensive list of Singer Manuals
Something I can't help mentioning is that the Singer 96-10 is a medium weight sewing machine intended for medium-heavy weight fabrics and possibly light weight leather if you're using the proper (sharp, awl point) needles. There are many machines more suitable for sewing leather as that may be what threw your machine off if you were driving it too hard. Another thing, because of the age of these machines, there's probably a fair amount of freeplay where it's worn down (modern industrial machines I use have no wobble on any of the parts). Many of the joints can either be clamped closer together or screwed in to push a cone in further, reducing free play.
At the time of writing this, I'm currently restoring a 96-10 and have completely disassembled it. I will be going through the touchy process of timing myself, when I get it back together.