RE: anyone built this model (aquastar pusher)
The Aquastar is the one with the low tail, the straight wing and the blue canopy.
The one with the T-tail is my design Seapup and needed wire struts to support the tail. It was very floppy without the struts, I have found T-tails always are.
I don't think the tail made a difference to the take off. I think it was maybe hull design. The most obvious difference I remember is that Sid's Aquastar had its step very far forward, ahead of the CG, whereas my Seapup had its step just aft of the CG.
Here is a Laker for comparison, and another shot of the same Aquastar that I just rediscovered. It was taken last year at Colwick Park, England. Whoever it was that bought the late Sid Sutherland's model brought it along and I took this shot. I don't think the new owner managed to get it to take off either. I don't have any flying shots.