As always great work and interesting posts Manfred. Glad you got a microart crawler kit. I really wanted to build it myself but it is way beyond me to do even a half decent job. I hope you do make it and post your progress as I am sure many people would really enjoy following your build.
With regard to crawler itself you might like this you tube video (though I am sure you have already researched this already, but just in case not)
Keep up the great work
Regards
Kevin