This spring I attempted my first air layer, which is on a Acer palmatum
"Shindeshojo." I was originally concerned that this cultivar would not
successfully air layer, but as it turned out, it did. By now it has
generated a number of roots along the cut and about three weeks ago sent out
a vigorous flush of new leaves.

I need guidance on the next step:

When should I sever and repot? While it has good new roots, should I wait
till the air layer medium is packed with new roots? Seasonal considerations
- is it okay in the fall to repot (we are in Houston, so Fall extends
through November), or is it best to repot only in spring.

What is recommended for potting medium when I repot? For the air layer it
was straight shredded peat.

Pot size - this is a fairly large tree that I'm severing, probably about a
1.5" caliper. But I've had more than enough heartache from potting in
larger pots. Should I keep it in a half/gallon pot, or even smaller, until
a string root ball has developed?

Feeding recommendations immediately after repotting?

Thanks,
Blake in Houston