David,
I don't need toestraps if I'm forward of the rear beam, and yes I do use these straps when solo (but only off the wind). When fully powered up with the kite in a blow, I'm trapezing as far back as I can possibly get, and the boat is planing downwind....

If we're two up, then my crew is just forward of the rear beam and I'm level with it (aft foot in the toestrap).