Your quilt is stunning and to think it is your first major quilt!. I will offer an opinion. Keep it very simple especially in the main body of the quilt. Stitch in the ditch would be nice if you feel confident; but, you could also do a quarter of an inch from the seam lines. Then you could take advantage of regular stitching on your machine or use a walking foot if you have one. If you practice on some scrap for a bit before hand I think you could do feathers on the border. This would allow you to do feathers and also not have to be concerned with a bunch of tight quilt stuffed in the harp space. We will look forward to see what you finally decide to do.