Thanks all for the many good ideas/tips!
I am thinking of getting Grosse valves for the car anyway as I have had good luck with them on my '68 122 B18. They are pretty inexpensive and now that the tank is producing crud free gas at the carbs, something that I had planned to do anyway. I am pretty sure the float levels (if there is no leakage/sticking) are correct.
There is also a possiblity that the exhaust system is producing too much back pressure which might account for excess manifold heat. The resonator is pretty rusty looking and may have internal blockage problems, the ex. system was missing from about 3' behind it (entire rear section gone). I cobbled up a 90deg. bend with adaptors to exit the ex. in front of the rear wheel. The car should be street legal on Monday, so I intend to have a local muffler shop bend up something in 1 3/4 or 2" pipe that runs (more or less) along the route that the stock exhaust took with a transverse muffler at the rear.
If none of these measures help then I guess it is time to make a 'real' shield, I put one on the rear carb and it does seem to delay the onset of the problem. I wonder if on H4s you could simply rotate the float bowl on the rear carb to the front (you would have to do something with the fast idle mech.)?

Again, thanks for the responses/ideas!
OK