I have been creeping on TT for some time but this is actually my first post!
So I happen to live in the same area as the OP and we met up to ride. He told me about this thread and his conversion. After seeing how nice it was on his bike I decided to take the plunge and start working on my own "cheapo FCR MX 39". I acquired an adapter from Jeff and then order a carb from ebay. I am using an FCR MX 39 from a 2008 KTM 525xc which was only $160! I have ordered the parts Jeff indicated in the OP and I am patiently waiting them and a few jets to show up. So far I have fitted the adapter to my carb and will update as I progress. As you can see below he has updated his design as was suggested in am earlier post to include a velocity stack design to reduce turbulence.
This is getting installed on my 2017 DRZ400SM that only has 550 miles. So far it has a Yoshi RS2 exhaust, 3x3 mod with a K&N filter, and Jetted. I also got lucky and picked up a set of dirt wheels at the time of purchase so there has been quite a bit of fun had so far