I put the vertical panel up most of the time, but agree the horizontal screen does the most work. I think the Windblox would work best on a roadster like the Miata; but it likely would be better than nothing.congrats - yes, I think it's a must have.
re: windblox - don't have experience with it but the design does not look as effective. I think the wind will rush in from between the seats, below the block.
I usually keep the vertical panel down as the windblocker seems to work just fine in that position. If it's really cold or if I'm with long-haired companion then I might raise the panel - there is a noticeable difference, but not huge. I think covering the rear seat well does most of wind blocking, and the Windblox does not do that.
I'd recommend it unless you have folks in the back seat frequently OR if you know it will be days before the top goes back down. Just flip down the vertical panel for better visibility AND so you don't look like a dweeb.Can the factory windblocker be left in position with the top up?