I didn't repot because I bought it in July. The soil is okay but there's a good bit of potting soil in there. The moss is from my yard. There were a bunch of exposed fibrous surface roots that I needed to protect. Will probably add some to the other side as well to cover the unseemly wire.
The Anderson flat is well known on this forum. It's a training container suited well for bonsai development as the entire bottom allows drainage and it is wide and shallow. But they are expensive to ship and really only good if you buy many at once. I have one and hope to buy a bunch off of
@JoeR before late winter (if he can find them
). If you just search the term on this site, you'll easily find an image. A google search can lead you to a reputable supplier.
Oh, yeah, I fertilize most of my trees with Osmocote plus. It's a good high nitrogen fertilizer you can get at any big box garden center. Hope this helps.