Looking at it i would say you need to extend it by at least 4 more boards to fit it in when the wheels are on other than that like Gav says it looks good like that
I can't take credit for the idea,in one form or another it's been around for years!
A couple of tips. Make sure your hands are clean as the Blu-Tac wil transfer muckiness to the model. Spray the light colour (Ocean Grey) first and remember when you lay out the 'sausages that they are covering that i.e. the sausage is part of the grey. The outer edge of the sausage is the edge of the Dark Green. It's surprising how often people get the grey areas too big and the green too small.
Firstly give yourself some credit it's looking good. Engine is very realistic I like the exhaust stacks. Camo is coming on and I like the machine gun detail. Keep up the good work.