Double male plugs are dead-man makers. You see one of those walk the other way.

Dual-gennies have special adapters to balance the load/throughput. To be honest I've never read up on how they work,but they'd have to use some kind.of isolater to.prevent backfeed between gennies.

Honda seems to have popularized the idea with their small gennies (1k/2k).

Its not a cheap solution, but its flexible.

I finally did some reading up on soft starts.

Turns out they're generally a switching power supply-some thing used by your laptop today.

Most of us are familiar with transformers-those wall-warts that turn 110v AC into 9v or 12v DC for small household items. Transformers are useful, but very inefficient- lots of current lost to heat.

Laptop makers changed to switching power supplies in the 90's (guessing the tech came down in cost).

Here's a link to a good description:

1. What is a Soft Start? - Electric motors & generators engineering FAQ - Eng-Tips

A hard start is just a giant capacitor and it only reduces the starting amps by around 10%. A soft start ramps up the compressor slowly reducing the amps by 70%. The soft start also extends the off cycle of the compressor to 3 minutes to allow the head pressure time to bleed off thus reducing the starting load even more. I installed one and now I can run my AC off my 2000 watt generator. The compressor starts so slow that you can't even hear it kick in. All you hear is the fan motor slow down a little. You can get one for $160 if you want to make your own enclosure for it and provide your own start cap. otherwise they run about $350.

what size generator to run ac
 

Yamaha makes an adapter to run dual generators. I haven't tried that but sure its fine. My 2000 watt Yamaha won't start my ac 13500 btu unit so I'm going to try a hard start capacitor.