Well, the simplest mod I can think of would be to gang the +5V lines from each power supply together, by soldering [ * edit: see below] the two wires together, and feeding into the existing IIci connector/s. In theory, that should sum the current capacity on the +5V feed of both supplies. That, or using the LC supply to drive the HD and floppy, leaving the IIci supply to run the logic board and Nubus - or vice versa, if the +5V rating on the LC supply is actually the higher of the two.

Are both supplies switched, and/or soft power-on compatible? If switched, it would be a good idea to gang them both to a single switch so they come on together. If soft-power, I'd suggest joining the soft-power-on lines. It's also probably a good idea to gang the ground line/s so they are both on the same 0V floor.

* Thinking further, I would say using a screw terminal "chocolate-block" for connections is probably better than soldering - it allows you to non-destructively experiment with different set-ups - and a simple way to adapt (say) an ATX supply at a later date. They're cheap, and as long as they are screwed down tightly and not subjected to cable strain, as secure as a solder joint. Connect the motherboard/drive plugs to one side, and both power supplies to the other. You can even label each line on the white plastic.

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