"You are far better in your case having a front PA scope and leaving it PA at 25 yards for the squirrels, if you don't touch it the PA is fixed "

Thanks, that does make sense!

I spent the weekend fiddling with a new scope, messing about with parallax, magnification, focussing ring, illumination and got a bit exasperated with it all - started dreaming of just looking through a scope and shooting something!