Yes D, it was my typo. I did mean ARF, not DW, lol.
According to Pombok's info, if the tube hole has the right diameter already, why further tapping is needed? The threads on the case is different to that of the gen tube? If that's the case, drilling is then necessary.
If countersinking is needed, what is the drill size to be used?
What's the difference of a gen click spring to that on the rep?
To me, the biggest hiccup is to get access of the gen crystal, which is almost nowhere to be found...…..