A code scan will tell you if the optical module is the problem. Pulling the cap will tell you if the HV section is beyond repair. Why guess? "Parts Replacement Roulette" is a very costly way to gamble.
Did you use Shoebox's guide to testing the ICM/Opti? You need to measure VOLTAGE on pins "A" and "D" of the ICM, not CURRENT. When cranking the engine, you test for AC VOLTAGE on the white wire to the ICM, not CURRENT.
http://shbox.com/1/4th_gen_tech2.html#opti_test
Did you test the coil using Shoebox's guide:
http://shbox.com/1/coil_testing.jpg
The price of a "factory" Opti has been INCREASING over the years. The only Opti's that are cheaper (1/2 the price) are rebuilt units, and units (cheap copies) that have been manufactured in China. These have terrible reliability records, often failing within a few miles, or even being bad right out of the box. Yes, some of them might last, but it's a matter of the failure rates. The cheapies fail a lot more often than the factory parts (Delco/Delphi).
Further complicating the issue is I've heard that GM is now selling GM remanufactured units, rather than new. I don't know if this is true, so there's another unknown in the equation.
I have heard rumors for years of the Mitsubishi optical module being available, but have yet to find one for sale. If you have a link, please post it.
The optical module in the Opti is good to at least 8,000 RPM. I've hit 8,000 RPM with mine, as documented in a data log (ooooppppsss... missed the 2->3 shift at the 7,400 RPM redliine). I only use the optical portion, but there are others who routinely spin the full Opti to 6,000 - 7,000 RPM. A buddy of mine also used only the optical portion, and he was spinning his 97 SS convertible (9.05 @ 156MPH at 3,850# race weight) to 8,000 RPM.
The difference in the 93 Opti/Ignition wiring is solely the PCM pinouts, and the inclusion of the tach filter.
1993 Opti/Ignition Wiring (courtesy of Shoebox)
http://shbox.com/1/93_ign_system_schematic.jpg
1994/95 Opti/Ignition Wiring:
http://shbox.com/1/95_ign_system_schematic.jpg