I have done the JL billet maglock on a couple of Radian lowers.
Those Radian lowers are tricky for a couple reasons:
First, the JL billet maglock only works on a standard mag release, but the radian has it's own non-standard mag release due to the ambi parts that interact with it.
I drill a hole into the Radian mag catch so that the pre-drilled JLbillet mag catch is not used.
Second, you can not drill a hole for the JL billet in the Radian lower because Radian already has a hole in the area where JL wants you to drill.
The radian hole is not in the correct place for JLbillet's mag catch to work.
The radian hole is there for you to install the ambi mag catch linkage parts.
The radian hole is about half-way into the spot you would drill for the JL billet maglock.
I re-use the radian hole and enlarge it to take the JL billet maglock in a different location than what JL tells you to do.
This does not matter because you can not use the pre-drilled JL billet mag catch in the Radian lower due to the ambi catch linkage parts not working with it.
The radian hole is very close to the lowers outside surface and opening it up to put the spring into it may cause the hole to break through the outside of the lower a little bit.
This does not effect function but it's not desirable cosmetically:
ARmaglock will not work with the Radian lower due to the nonstandard mag catch slot and ambi parts.
Hogue freedom fighter will not work if you want to retain the right-side ambi lever that sits right where you need to drill for a freedom fighter.