I'm glad to hear that things are going more smoothly @jneilon, that's great news. 
I'll do my best to help with versioning. The easiest way to get version information is to look at the Product Version in the Properties->Details of the 3dsmax.exe. To access this from MaxScript use:
getFileVersion "$max/3dsmax.exe"
A breakdown of Max versions is below, I hope it's helpful: (FCS = First Customer Ship)
Release: 3ds Max 2018 | 20
Build: 20.0.0.966 | 20.0.0.966 FCS
Build: 20.1.0.1452 | 20.1.0.1452 Update 1
Release: 3ds Max 2017 | 19
Build: 19.0.1072.0 | 19.0.1072.0 FCS
Build: 19.1.129.0 | 19.1.129.0 ServicePack 1
Build: 19.2.472.0 | 19.2.472.0 ServicePack 2
Build: 19.3.533.0 | 19.3.533.0 ServicePack 3
Build: 19.4.838.0 | 19.4.838.0 SecurityFix Public 1
Build: 19.5.917.0 | 19.5.917.0 SecurityFix Public 2
Build: 19.50.781.0 | 19.50.781.0 Update 1
Build: 19.51.835.0 | 19.51.835.0 SecurityFix 1
Build: 19.52.915.0 | 19.52.915.0 Update 2
Release: 3ds Max 2016 | 18
Build: 18.0.873.0 | 18.0.873.0 FCS
Build: 18.3.490.0 | 18.3.490.0 ServicePack 1
Build: 18.6.667.0 | 18.6.667.0 ServicePack 2
Build: 18.7.696.0 | 18.7.696.0 ServicePack 3
Build: 18.8.739.0 | 18.8.739.0 ServicePack 4
Release: 3ds Max 2015 | 17
Build: 17.0.333.0 | 17.0.333.0
Build: 17.0.630.0 | 17.0.630.0 FCS
Build: 17.1.149.0 | 17.1.149.0 ServicePack 1
Build: 17.2.259.0 | 17.2.259.0 ServicePack 2
Build: 17.3.374.0 | 17.3.374.0 ServicePack 3
Build: 17.4.476.0 | 17.4.476.0 ServicePack 4
Release: 3ds Max 2014 | 16
Build: 16.0.420.0 | 16.0.420.0 FCS
Build: 16.1.178.0 | 16.1.178.0 ServicePack 1
Build: 16.2.475.0 | 16.2.475.0 ServicePack 2
Build: 16.3.253.0 | 16.3.253.0 ServicePack 3
Build: 16.4.270.0 | 16.4.270.0 ServicePack 4
Build: 16.5.277.0 | 16.5.277.0 ServicePack 5
Build: 16.6.556.0 | 16.6.556.0 ServicePack 6
Best Regards,