Idleing Issues!!!!
No problem. Actually 10-12 degrees is just close enough to get you into the ballpark. I forgot you mentioned earlier that you have a advance type timing light. With that you can get it real close. What you really need to get it to is about 34 degrees total timing. That is what it should read when you have the vacuum advance disconnected and the engine revved up to about 2800-3000 rpm in neutral. Then lock your dist. down and hook the vacuum advance up and your good to go. Actually my 360 timing is set at 16 before but that's because I have a Mallory dist. that has adjustable advance and need more initial timing and less advance for my larger cam. As far as checking the balancer goes. The only way I know to do that is do a good visual inspection on it and check with a dial indicator. I believe if it actually came loose enough to slip it won't be straightand since the 360 is externally balanced it would probable vibrate bad if it slipped. The mechanical way to check it would be to use a dial indicator to find TDC on piston #1. When #1 is on TDC the balancer should be on zero. If you don't have the tools to check that the visual is all you can do.
I see what you mean about the acc pump causing hard starting since it gives no pump shot.