Yet another alternator problem

My turn in the barrel with alternator issues.

I have a PA-24 250 with an InterAv 50A alternator conversion installed
that has a chronic but transient issue that appears to be associated
with regulation. Observed symptoms include:

- Overvoltage relay kicking the alternator offline when the gear motor
shuts down when running the gear down (but not when running the gear up).

- Overvoltage relay kicking the alternator offline with demand spikes
(like hitting all the landing lights at the same time)

- Transient discharge indications on the EI volt/ammeter when running
the strobes.

I've replaced the spike guard cap, rebuilt the wiring harness, made sure
that the grounds are clean and that there are no ground loops. Measured
resistance between the regulator output and the field terminal on the
alternator is less than one ohm. The battery is new and the ship has
copper cables.

This issue isn't new; it's been observed with the aircraft since we
purchased it and we're still trying to track it down. The issue with
running the gear down is both the most common and the most disturbing,
since the last thing I want to do is take all the avionics offline in
order to recycle the alternator while swimming through the marine layer.
I'd considered putting MOVs on the gear motor, but that doesn't
address the real problem, which is that the regulator seems slow to
respond to changing load, causing overshoots when heavy loads drop off
and droops when loads come on.

So, two questions for the group:

- Anyone have a clue regarding what in the world is going on here and
- Does anyone know of an alternative to the InterAv conversion for the
O-540? Even my hangar mate with the '68 Cherokee has 60A alternator...

Thanks,
Chris.