The Moebius - starting on the cockpit

I need to get some Plasticard before i can continue on the lower section of the Moebius, so i've made a start on the cockpit seat.
Eyeballing it, to be true to the illustrations i figure i'd need the ship to be 1/48th scale but:
(A) i've not much money this close to the finish of Christmas to source a suitable kit,
(B) 1/48th would make it a quite small craft and the interior would be VERY cramped,
(C) i've plenty of 1/72nd cockpits to use,
(D) it would make for a more decent size ship,
(E) i'm more likely to find suitable figures to stand on top.
So here's what i've done - started with a cockpit seat from a modern fighter kit and built around it with Plasticard and detailed up with kitbits.
It was tricky cutting the Plasticard to match the curve of the inside of the clear ball i'm using, but got there in the end.