Booms are from B&Q, 10.5mm X 10.5mm. Had to notch the rear boom a little with a file to get it to line fit in the tail section (4 screws close together). Front arms are 450mm and rear is ~50 I think, there was some maths involved but I was a little drunk

Last year I tried a few combinations from 480mm all round to about 300mm but was on smaller props too (8x4.7 vs 10x4.5). This platform is more for slow, stable flight. It's good to experiment to see what you like as it's so easy to lop zip ties off and chop a bit of wood down
This combo has plenty of lifting power and can fairly shift!
Make sure you trim the motor shaft, really easy to ruin a DT750 with stock length shaft
Going to get myself an APM flight controller and a Mobius Actioncam for the summer