I wouldn't be too hasty getting rid of your aux. alternator until you're satisfied that you have something that works. The 82's were very unique. The Main alternator was only used on the 82. I'm thinking the 82 was a tried model to prove that dual alternators could work. The 84-89 had a larger Main Alt with an Aux alternator.
As far as your question about the regulators goes. Jack at
www.roadstercycle.com has your answer. The series regulator/rectifiers are definitely the way to go and Roadster Cycle is the only supplier of genuine Shindengen regulators I know of. The SH775 series regulator will do the job as proven by Neville but it might be taxed at 35 amps maximum with a maximum steady output of 27 amps. I think the SH847 with a maximum of 50 amps is a better choice but it's $50 more than the Sh775. If you're going full out LED's then definitely invest in the SH847 (as noted by Roadster Cycle). It's better suited for running with low charging requirements.
Please take the time to read Roadster Cycle's web page. Shunt regulator's which are the stock regulators or the Shindengen FH020AA or the FH010AA's are Stator Eaters. The series regulators ( SH775 or SH847 to name a couple) run the stator as required to charge the system. Shunt regulators run the stator at 100% output all the time and dump the excess wattage to ground via short circuiting. How stupid is that??
Let me put out some numbers here and Hopefully help increase the understanding of what's going on.
The Shunt regulators run the stator at 100% output. The output either goes to make up the losses in the electrical system or it's shunted to ground. That means the stator is putting out 14.5 volts @ a maximum of 35 amps? all the time. That's 507 watts of energy. 507 wats = 1732 BTU's of heat. That heat has to be taken away from the stator which is done by the engine oil. If the engine oil doesn't completely saturate the stator and remove the heat and allows the stator to get over 400 F, the varnish on the stator wires will burn off becoming carbon and short the stator
Series regulators open and close the feed from the stator to meet the demands of the electrical system. When you start the bike, that initial draw on the battery from the starter needs to be replenished and the charging system goes ahead and tops up the battery. Then things relax and the running electrical draw only needs to be met. The series regulator only demands what it needs from the stator, so if the running requirements say during the daytime with no lights running is maybe 10-12 amps, them the stator is asked for 14.5 volts at 12 amps = 174 watts which equates to 593 BTU's.
So, if you were a stator, would you like to run at 1732 BTU all the time or would you like to run at 1732 btu for a couple of minutes and then at 593 btu for the remainder of the time?? No brainer here right??