Honestly since you already bought the pill, just buy LED and driver spec for the pill.
If it fits loose in your light, just shim some aluminum can around it or something to affix to your light.
I’d go with XP-L Hi or SST-40 for effecient brightness and a simple biscotti 2800ma driver with adapters to fit
if all doesn’t fit then just save yourself some hard work and get a Convoy S2+ or a C8
Without any details we are all speculating only.