My situation is similar. 30 miles on a 60mph road to get into the "big town" of Spokane. Overdrive is a must for me.
I spend a bunch of time looking at the TKX and T56. In the end I was leaning towards the narrow ratio TKX if I went with the 5 speed. But I was looking at a 3.55 rear gear with it. It cost about 100rpm on highway but seemed to be the better setup (to me). I liked that it would pull better in 4th than the wide ratio with 3.23. And I like the more even splits between gears (34/32/21/32) compared to the wide ratio (39/32/25/28). That said, a 3.27 first gear with 3.23 gears is going to outpull a 2.87 first with 3.55 gears.
In the end, I decided that I want the double OD of the T56. If I am cutting the floor out anyway, it's not much more work. The trans by itself is only like $500, but I think the kit is more since it takes some bigger cost things. But one of the companies you mentioned sells a cast aluminum bell that should work (I think) and keeps costs down.
In the end, the T56 with the 2.97/0.50 gears (TUET-11012), 3.55 rear gears and 245/45R17 tires put me right in line with how my 2015 R/T drove. And I loved how that one cruised.
I actually got the cost down to about $5500 sourcing most of my own parts and keeping my existing clutch outside of swapping the disk.
But that was with an LA, not sure how it will pencil out with the G3 swap I am working on.
Beyond that, I can't help. I got quotes from both companies you mentioned, plus Modern Driveline, but don't remember enough to give input on who would be the better source beyond the fact that I think all of them were really expensive for the hydraulic conversion kits they offered.
