While I am new to the whole MZ thing, I seriously doubt that aligning a plastic sabot on the lands will have any effect, what-so-ever. The pressures and speed happening in that barrel will quite likely over-ride your best efforts.
The plastic is going to "find it's groove" as soon as it contacts resistance, and then act accordingly.
I personally think that, scientifically, the tighter the fit of sabot to bore, the more influence the rifling's and lands will have. With-in reason, of course.
It simply makes sense that a loose fit is probably going to allow some "slippage", if you will.
A snug, (NOT over-tight), fit will impart a truer spin on the bullet after it leaves the sabot. We are talking thousandths of an inch, here.
After all, when we rely on a piece of plastic that is intended to be discarded after leaving the muzzle to import the spin on the bullet, under tremendous speed and pressure, well, let the imagination run wild, but close contact between the two seems logical, to me.
I am currently under the assumption that that is one reason I, as a total new-be, am able to achieve pretty good groups with-out much experimenting. Granted, I have been well-guided from the get-go. But so far, snug, not super-tight, loads, with 100 grains of Bh209, have been stellar.
My thanks to Sqezer and Ron. They have made my journey so enjoyable, and my "what the hell" short!