Just of the top of my head, I think you'll find that once established in a steady state descent ie not accelerating vertically, that the load factors are unchanged.
Change the condition to one where the a/c is accelerating downwards eg just starting a descent, then the trigonometry for it would 'simply'
involve subtracting the downwards acceleration from that due to gravity & using the resultant net vector added to the centripetal force vector.
I think (but can't recall exactly) that the formula is:
....tan AoB
LF=---------
....'g'
or some variant of those terms. Too lazy to work out the maths correctly.
I'd say the the 'g' term would be replaced with the net result of gravity's accel - the a/c vertical accel.