Black spot or old leaves (Chinese elm)? Also advice on potting/styling welcome.

[bako_bonsai]

Is this tree alright? Are the spots something to worry about?

I got this tree delivered on July 31. It came from Brussels Bonsai and shipped from Mississippi to Central California (zone 9b). There were a few yellow leaves, many simply broken in half, and some with spots when it arrived. I trimmed most off (except some hard to reach ones). Other than this it seems healthy and has produced some new healthy growth (you can see in some pics).

When it arrived I acclimated it to our heat (sometimes 110°+) in the shade of my healthy, mature (~3 ft diameter, twice-as-tall-as-my-house) Chinese elm. It was in the partial shade for about a week now it's in full sun. My large Chinese elm does not have spots like this and I can't remember it having similar spots at any time. My mature elm does lose its leaves in winter (around dec. or Jan.) so I'll expect the same from my bonsai.

I'm assuming it's best to wait until spring to repot into a bonsai pot and style for the first time. Does that seem most reasonable?

 

[Bonsai Nut]

The tree doesn't look that bad. Sometimes when a tree is shipped during hot and humid summer months (think Mississippi in August) you will get some humidity/heat damage and/or fungus going crazy in a plastic bag. I'd keep it in partial shade until you see it is fully recovered. It may drop some leaves initially, but you have plenty of growing season left. You may find that it pushes a second round of growth in October/November, and doesn't even drop leaves this winter.

 

[Shibui]

I would not be too worried about a few spots on leaves either.
Spring is usual time to repot but I know tropical growers who tell me they repot any time of year because Chinese elm never goes dormant for them.

 

[bako_bonsai]

Wonderful to hear! Can't wait to repot and style it in the spring.

I got a bit of practice wiring some of the thinner branches on the mature elm this summer. I'm hoping they'll harden up by winter and I can take the wires off then air layer them in spring.