Thanks Bubba Pearson - I'll definitely experiment and aim for higher quality on the next batch (and will also be trying decals). Your basing suggestions are very useful!
You do a good job on these and it's a bit difficult, given the material out of which they're made. I think a bit of very subtle two-tone highlighting and some almost not-there 'weathering' would help your work considerably. You could experiment on some old, beat-up models and scraps, then perhaps go back and modify your existing paint jobs? You also could keep these as-is and have them to look back on as your skills improve. Also, try to keep in mind the actual size (scale) of these beasties when painting; everything should be small and tiny-tiny, as the 'actual' figure is huge. This is especially important when finishing your bases -- for example, that static 'grass' would be a veritable jungle of super tall foliage in this scale. In this case, maybe some TINY branch bits for trees and detritus, on top of simple green flocking (over a very fine sand (possibly even baking powder) painted 'dirt' base) would contribute more towards an accurate representation of the bases for these unreal brutes. :-) Good work!