Falcon F-16 v2.0 in multiplayer....Mac Plus <-> 486 PC!

Last year, I bought the boxed game of Falcon F-16.

In the supplemental documentation added with v2.0, we can see this paragraph:


Goal:
serial link multiplayer game between a vintage Mac and vintage PC using a null-modem link between the two!

Mac side: Falcon F-16 v2.0 (the update that brought multiplayer for this port) running on a Mac Plus
PC side: Falcon (I think you can get away with the original which allows mp out of the box) running on a MSDOS6.22 486 IBM that has a DB9 male serial port.

I bought a cable on ebay blindly, it was cheap, and the wiring doesn't look promising. this is the diagram of how the pins are linked together on both ends of the cable



I think a potential solution is:

cable 1: Mac DIN8 male to DB25 male regular printer cable
cable 2: PC DB9 female to DB25 female null modem cable <- not easy to find

or perhaps
cable 1: Mac DIN8 male to DB25 male regular printer cable
cable 2: PC DB9 female to DB9 male null modem cable
dongle 1: DB9 female to DB25 femal

I definitely need help from people more knowledgeable about these null-modem solution, bonus points if you've done cross platform connections with RS422 and RS232!

I got answers from the other place, here's a collection of notes on the topic (thanks @joevt)


https://forums.macrumors.com/threads/serial-app-to-old-world-of.2429025/post-33239745


I think I'll do a 2-prong approach. Irreversibly modify the badly wired cable I have according to these notes, but also figure out a solution that can be bought in the market now.

So I bought these and they are on the way: