Atomic 22, No, The Chrysler reg is for a field excited alternator. The field excited alternators control the output by controlling rotor current, So when the electical saystem don't need juice tha reg shuts the alternator off.
The PM systems run at full output all the time. When the electrical system don't need juice the regulator shunts any excess output to ground. This makes the reg/rec very warm.
Big JIm, Even if you built the Radio shack rec, you would still need a reg, A big Zener diode at the right voltage would work.
I would try another PM type reg/rec. The five wire one, 3 hook to 3 from the stator, one hot, one ground.
If you keep blowing the Pamco's your voltage reg isn't doing its job. Any spikes over 16 volts can kill the Pamco.
I might try hooking in a small battery to run just the ignition. Leave the rest of your system hooked to the PM. Hook a volt meter up so you can carry it with you and ride the bike watching your volt meter. If it goes too high at speed then your reg is bad. It should stay at about 14.5 volts no matter how high you rev it. As far as hooking in the tail/ brake light it shouldn't effect the ignition. Just check to be sure its not shorting to ground and it's not on the same circuit as the ignition.
Thats about all I can think of, Pamcopete may have some other ideas on why the Pamco is having trouble.