Hi flatdog - there are several things in MoI v2 that make this a lot easier.

You can get the current v2 beta from here: http://moi3d.com/beta.htm

In MoI v2 there is a new set of snapping functions for snapping a point on to a surface, so you can just directly draw a circle on to a surface and it will be aligned with the surface normal, like this:




Also another option is to use the new Transform > Orient command which lets you position an object or copy an object aligned to a surface, see here for some demos:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3179.1

- Michael