Iris Cohen schreef
Last spring I got mad at this juniper, cut the top off, and planted it in
the ground for a few years.
I inquired as to whether I could give the Shimpaku the same treatment.

+ + +
Short answer: Yes, you can cut the top of your 'Shimpaku'.
What this will do is another matter.
You are unclear about the effect this had on your J. squamata.
Also there is a mystery. The way I count, if you cut off the top last spring
and put it in the ground a few years, then for you to know the outcome now
is either 'botanic fiction' or you found a way to create a time loop?
PvR