Hi Simon, the easiest way is to join the 2 pieces together and then use Fillet at the shared edge. Another possibility is to cut away some space between them and then use Construct > Blend to build a smooth connecting blend surface. If you can post your .3dm model file it could help to give better suggestions.

> I've used moi for a while but never really used the whole patch style modelling process so any tips on
> this process would be greatly recived. For example, should I avoid using boolean wherever possible?
> Should I keep each 'patch' as separate objects?

Well in general it's easier to avoid building things in a "patch by patch" method and try to work more with solids. If you are working with surfaces only then typically you would not use booleans which are focused on working with solids and instead use Edit > Trim.

It would be easier to give better advice seeing your current model and some description of your overall goal.

- Michael