Using an L plate was what i had in my head to give more travel, will be an interesting project. The only solenoids i managed to get my hands on were from old washing machines, not sure on the pullig power or effective throw they have though. I used one on my master caster, but the EMF it produced, messed with my controller.
I didn't have a tap when i made mine, i was lucky enough that the plate i needed threading fitted into my lathe, so i cut it that way, then i knew it was perfectly straight too. I have only ever run Lee sizing dies, i did make a few extras out of 4140 to size some .40s, they did the job.