Advice about creating a height map: there's two good ways to have a go at it.
(1)
Several layers, each one corresponding to a certain height - layer on top being the tallest.
You can use any color and recolor it at any time, as each layer should only be either solid color (100% opacity) or transparent.
PROS: easy to make adjustments to topography; translates neatly into a modern topographic style map
CONS: depending on the number of layers it can be (very) time consuming; if you want to turn it into a sort of DEM, you run into a "steps" problem
(2)
One black&white layer, with white being the tallest
If you know what you are doing and you have a tablet/graphic pen, this might work better. And if you know your ways around gimp/photoshop you can do a lot - have a look at what Charerg is doing with his world!
PROS: It's already a kind of DEM, easier to port to Wilbur for detailed erosion, for example.
CONS: I'm partial, but I think it might be harder to work on without messing up local altitudes all the time.
Concerning feedback to the present state... your tectonics, hmm, humm, either invest the next 3 months redoing it or never think about it again