I went with this one. In the not scratch resistant model as I didn't think I would need that on the rear panel. Front windshield it's a must.
HONDA PIONEER 500 BACK WINDSHIELD
I installed it as part of my plan to fully enclose the cab and heater install for winter. Far as dust goes it does help as long as you don't have a front windshield, or have a half windshield, or have a fold down like mine and have it folded down. When the full front windshield is up it seems to impede the air flow through the cab and dust likes to boil up from off the tires cloud up in there. Not a problem for me as when it's dusty I usually have it folded down and it keeps it pretty clean.
A word to the wise. If you install a full back panel you will need to check and probably clean your air filter every one or two rides if it's dusty out. The air flow is blocked above the air intake and the engine sucks super dusty air right off the tire. I made that mistake when I first installed it and drove about 250 miles in dusty conditions before I checked the air cleaner. It was the most dirty, looked like a layer of mud on it, air filter I have ever seen.
So instead of cleaning it constantly I snorkeled it for better air intake location and that fixed the problem completely. I built one very similar to this post by
@Texas_Newfie
P500 - A Simple Snorkel