Very cool and thank you for the step by step. Are you using squadron green putty? If so where did you find it?Have you thought of auto body filler? Thin layers should not heat up enough to damage plastic and you could get it setup much faster. It would be just as strong as milliput and just as easy to sand. Just a suggestion.
Snitchy sends.
No I've not used squadron green putty for a while, didn't like the fumes - I'm using liquid greenstuff. I used to get it from Modelzone, but those have typically closed but you can get it on ebay.
A picture with a 28mm figure for scale...
drilled hole in top for steering
and it fits!
next up spraying it to see how wells the surfaces have worked...