Hey Harrg, this is looking great. Really good looking and convincing. I think Charerg gave you good hints concerning the probable tectonics.

Thanks for calling it my style, although it's a general topographic style that I copy, just like you do, so I can't take much credit. I think you're in for thousands of man-hours of work to finish this map, it's a huge area and you've got a seriously big file. On that note, I wish you strength, perseverance and a lot of free time, because you're going to need it.
One advice: if you ever turn this continent into actual maps, you can leave less ocean around the land and maybe even not show all the land - large continents look larger on a map when not all its ends are seen.
Second advice: save a copy of this, in poor quality, smaller fize size, and get in on Google Earth as an overlay. Then, from there, choose where this continent would be and how big it would be. Then, using the grid (latitude/longitude) and the ruler tool, you could establish size and location to your liking.