Thanks, I remember Tim mentioned your build and asked about the mount a few weeks ago.
The biggest reason I take on a project like this Dart is to learn how current upgrades / changes pan out and start thinking on what to improve for next time. While the first version of the crossmember / transmission mount was built specifically for this 6.4 build, the next version (already at the laser cutter) 8HP70 A body 2.0 mount will be slightly different to accommodate "stock" (higher and rearward) engine location.
Definitely keeping and extending the height adjustable loop. Small pilot holes are located in the loop to facilitate where to plug weld or tap / bolt to the floor pan. I am a fan of flexibility for updates and changes so while welding is great, it could be a PIA down the road.