Further to my previous post, I have now found a way to add the kind of waypoint routing option that the Moto edition skin has to the regular Decent skin (and possibly to any other skin).
I came across this on the GPSPower forum. There are lots of different UX files, which are kind of like plug ins that add certain functionality to iGo. There is one called "skip waypoint" that does what the Moto skin does (it might well be that this is actually how it is implemented in the Moto skin), i.e. you can set a certain distance around the waypoint where the routing will assume you have reached the waypoint and dismiss it and route you to the next waypoint, so you don't have to hit it exactly.
You copy this UX into the UX direcectory of Primo (create the directory if not already present) and you can set the radius around the waypoint that will let the programme assume you have reached it. I haven't had opportunity yet to try it with an actual route, but it installs fine and I can set the radius/distance, so hope that it will work.
So, I will just stick to the Decent skin (on which the Moto skin is based), which runs fine on any resolution and has a display which I like.