I don't think there's a common standard, but most built recently have doors that are 40' wide.first span, what can you safely get in a "standard" T hangar model USA?
The tandem would give great visibility, especially if we can get the pilot's head in front of the LE. The weights/CG weren't looking good when I gave it a quick try, but I think Pop's had things worked out. When flying with others, across is a lot more fun. If it matters, Vans sells more of their side-by-side configurations than tandems.2-3-4 seat? As Pop said tandem with passenger in CG and pilot in front for visibility, if a tandem 2 seat the rear seat need a stick and pedals and a EFIS or it will be boooring to sit there.
The D-motors are pretty rare in the US. Lots of people know about them, but few are flying.Revmaster or D-motor, the latter is 88 HP at 2800 and some 10 kg lighter each. to a cost.