Those 8 pin adapters work. Below if a photo of the same one by the same seller Grogan, and like I said I have used every single 4 pin mic I have on my Icom 746 just for shits and giggles and also to see if the 2018 extreme would sound any better as well. Also, only issue with the REA setup that I can see is that it's for AM only. It specifically states will not work on SSB. Or it's not for SSB use as they say. It's made for AM only. I too looked at those once but without the use of SSB it's not worth much to me as I am on SSB 99.9% of the time. The optima MK3 is not an audio monster on AM. It's more of an SSB radio IMO. The added filtering and such are all for SSB and not AM mode on the optima. Just some food for thought.
Now if you plan on using it on other AM radios and such it will be a great tool. Also for messing with the TX audio and being straight plug and play have a look at these. Price isn't bad and even has make offer for one. But for the cost I think they are nice. They did have an 8 band one as well, but the 5 band one wouldn't be bad. I have been saying I may get one, and may here soon! Just waiting for all bills to be paid and the hobby fund to be replenished
. Then I may get one and see how well they actually do.
When you get the REA unit, like said, please post up some pics of the unit and how it performs as well. Looks like you had s good run of stuff that was bought. Where did you get the Optima MK3 from?? Or did your already have one?? If I were going to order one now, I would pay the little extra, ($35-$40) and get it directly from the dealer. You'll get an upgraded mic with it that is supposed to sound pretty good as well as the warranty and a tune and alignment before it comes to you!! All grest benefits for the little price difference between buying from Yeticom versus getting one off of EBay. JMO on that. At any rate have fun with the new stuff. And don't forget to post up some pics. What antenna you planning on running? Or are you all set there as well?? Just curious.