After deciding that blender is far too slow / inefficient for texture painting, I've been looking at alternatives. I couldn't even get many of the other apps to run on my lowly PC, as an Intel HD 3000 was not good enough for them.
So it typical 'do everything yourself' mode, I decided to write my own. It has taken about a week so far, on and off, so I consider it a good investment in time as it should make asset creation much faster.
This looks really good. Nice improvement.
Two small pieces of advice. Make the artwork for you:
In this case you could use different shaped platforms, to allow players to quickly see what turret is what without zooming in. Even if just simple shapes; in fact using simple shapes as a foundation is a great idea.
Second, use references:
Even professional artist uses references. Lots of artist use simple shapes to make complex art. https://www.deviantart.com/tugodoomer/art/env-obj-52-573913173 Looking at their work should inspire some of your own ideas.
I Like the depth of the platforms and your roundness looks visually correct. Good work.