The original hurst roll control (line lock) came with a micro switch that was secured to a manual shifter with a large rubber band. The same can be used on your column shifter.
I have a roadrunner with a reverse pattern manual valve body that I use with my column shifter, but that car doesn't use a line lock.
On my 62, I use an electric travel trailer brake (don't tell anybody, I don't think it's nhra legal) with a switch on the back of the shifter. This location only works in my application because of the way the trailer brake functions.
On my 'tina, the line lock switch is built into the shifter handle of the turbo action shifter. Lots of people have transbrake buttons on the steering wheel, but mine is on the top of the trans tunnel (non stock, tunnel higher than normal) so when I let go of the brake my hand goes TO the steering wheel instead of away.
On my opel, I put a switch in the pistol grip handle for the line lock.
Do you shift manually while in, or pulling out of the water box? If so, it needs to be on your column shifter. Maybe rubber band mount, with the wires concealed under chrome tape on the back side of the handle.
If you're not shifting manually, you can put the switch anywhere you want.