Will a rear window help with the dust tornado with a half windshield?  Looking at a vented rear but don't want a full front

[2015 Z Force 800 53/Trail EPS]

Yes. It's almost a must with a full front but in any case it will hold the dust vortex back. However do know you will still get some in through the door ways. Not much with a half-shield though....it will blow it out pretty well.

Yes it helps a lot, we have a half windshield on ours and before we put rear glass on
the dust was terrible, with rear glass very little dust.
Of you don't use a rear glass you're better off without a front glass.