"Can you just push the pulley further up the shaft and leave the crankshaft sticking out an inch below the pulley?"

No it's a stack pulley.

I have only cut 15mm off the crankshaft or I wouldn't have had enough thread left. I have also had to raise the engine about 12mm. I will have to grind the top off one of the steering shaft retaining bolts to stop the belt from rubbing. The deck belt only runs straight when it's on the highest setting now. I really think this is the wrong stack pulley.

How much would a stack pulley for the VRO 40-12 GXT cost?