OMG updates!
After 2 days of vigorous sanding, filing, and dremelling, this is how she sits:
The receiver is in, and the KJW trigger guard is in. I chose the KJW trigger guard over the original Enfield piece (which I just bought 2 more of, doh!) because it also serves as the magwell for the magazine. For best fitment of the mag, will have to sacrifice using one original piece.
The mag in place:
Eventually the plan is to fit an Enfield magazine up with the KJW mag.
Stay tuned!