You can try to crutch it up by using more timing. I would hook the vacuum advance up to manifold vacuum to begin with.
Dial in around 18 degrees or so of initial, be sure the total stays below 36 degrees or so. You may need to modify the distributor to make this happen.
Lower the idle speed back down after using manifold vacuum, also readjust the idle mixture screws to give the highest vacuum/idle speed. This will help the idle to stabilize some.