Thanks so much for the comments ☺ I plan on doing a demo video showing this off soon.
In the meantime a brief update, I changed out the Ledengin for a GGR tri cree xpe2 and it's much much brighter!
Standard MR on the left, single die original board conversion on the right.
Before:
After!
No contest, even shining through the thin neck the white overexposed 'core' is easily up to the tip whereas the red Hasbro conversion fades around half way ☺