First, I would try a a heat shield around the starter.

Then if that didn't improve the hot starts, do this:

First, if you haven't already either get a dial back light, so it's not a guessing game what your timing is, or get the appropriate timing tape for the Pontiac engine. You are wasting your time if you can't properly document your settings and changes.

Then, get an adjustable vacuum advance can. Set your timing for a to the point at which it will restart when hot. Use this as your initial baseline. Now hook up your stock vacuum can to full manifold vacuum instead of ported, while the engine is running. Then note the new idle rpm (yes you should use a tach), and the appropriate timing. Your idle speed will increase, again don't adjust it yet. Next, pull the distibuter and install the vacuum canister per the instructions. Re-install and reset your initial timing without vacuum. Then connect the vacuum again, and adjust until you get close to the stock setup. Then fine tune it by measuring the highest manifold vacuum or highest idle speed (rpm only if you don't have a vacuum gage). Then reset your idle speed down to the desired level. You also need to adjust your idle mixture.

You should also verify your total mechanical timing with the vacuum canister disconnected. Since don't have accurate initial and maximum mechanical advance curves, you are risking engine damage. You can buy a dial-back timing light, or there are digital ones that include a tach if you don't have one of those.

The money you spend on these two pieces of equipment, could save you from thousands in engine damage, lots of time tuning (that you could be using for driving), and allow optimum tune which gives you the best performance and fuel economy.