Largish precision mitre box suggestions?

[Michael Morris]

I'm just starting down the minefield that is building garage resin kits.  I'm a spacecraft/rocket modeller and on one of the kits I've got some of the 42mm diameter cylindrical parts have ends that are not exactly what one could describe as square.  I have a nice Tamiya #74024 large craft tenon/razor saw (with 0.3mm wide blade) which would be ideal for cutting the ends of these rocket body parts to make them square. 

https://www.tamiya.com/english/products/74024/index.htm

However, to do this I'll ideally need a largish mitre block to accommodate the 42 mm diameter rocket stages yet the mitre block needs to have thin enough slots for the saw blade to accurately hold the Tamiya saw square.  Any suggestions?

 

Thanks