DIY Parallel kit for inverter/generators

Hoping some RV.NET diy'ers can help me out. Thanks in advance.

I purchased two Pulsar PG2000iS 2000W Peak 1600W Rated Portable Gas-Powered Inverter Generators for my travel trailer.

I planned on running both in parallel when I need A/C but all the sources for the pulsar parallel kit are out-of-stock and my back-order with Amazon has been unfulfilled for months. I need to explore options.

1. How likely is it that a parallel kit from another manufacturer would be compatable with my generators? I can get honda, smarter tools, ryobi kits locally but not sure if they will work.

2. Can I build my own? I have access to an excellent electrical supply store and I have a great electrical guy at my workshop who will do the work but I need to know what to build.

I have seen a couple very simple but effective builds like this one...

***Link Removed***

I am weary about this setup because I have read that I really need a chip to put the two generators in sync. Is this true?

I guess this is what I get for buying an "off brand".

Any advice you may have would be great. Thanks.

More photos for context here in this album...