Electronic spark control problems

[cyclone85]

I did a timing check on my 85 silverado (LE-9 305) the other day and found some weird problems. First of all, with the vacuum advance hooked up I am getting over 20* of advance at idle, and when I rev the engine up it does not advance any, it just stays at 20*. If I unhook my vacuum advance, plug the line, and then set the timing at the recommended spec (4*BTDC), I have to retard it a bunch as soon as I hook the vacuum advance back up in order to get it to idle smoothly. In fact, the timing is set so far back that with the vacuum advance unhooked it will barely idle. I have read the article on disabling the ESC and I wonder, is that what I should do? Will doing so kill all advance functions on my distributor and turn it into a dog?

Also, is the tip in vacuum switch really needed? Can I just run a jumper across the wires at it to prevent it from retarding my timing whenever I accelerate?