Salvaging storm damaged Ginkgo

[Distraxi]

I have a Ginkgo tree that lost half its trunk in a summer storm (yes, summer: I'm in New Zealand) and I'm hoping for advice how/whether to salvage it.

The backstory is that I recently bought an overgrown property and have been clearing most of it and keeping those few trees which look saveable. The ginkgo was in the latter category. It's been lightstarved on one side so has grown asymmetric, it has codominant leaders (both now broken), and (demonstrably) was on the spindly side, but I figured a few decent prunes and some light would sort it out over time. I'd been planning to make a start this winter - now nature has anticipated me. It was about 20ft tall: it's now around half that.

Assuming I'm going to try and save it,
The secondary trunk will clearly have to go at some point - better to take it clean off now, or just clean it up and leave it till the tree's recovered form the initial shock?
Should I take the main trunk back to a strong lateral and bend that up to form a new leader, or just cut it off, wait till sprouts form and pick a strong one in a year or two to be the new leader?
If I'm going to retrain a lateral, is it valid to lash a post to the trunk and use that as a stake to pull the lateral upright? It's too high to use a ground-based stake, I think, though I could probably use a couple of guyropes attached at ground level to hold the leader up.
Any other advice?

A couple of pics attached.

Thanks in advance,
Dave

 

[derwoodii]

I think you answered your questions very well with various measures to make the best of what you got... Ginkgos a tuff tree species used as Bonsai & been around for 270 million years so a hard careful prune should not impact too much.. Beware of bark sun scalding due to its rapid exposure & add some deep mulch & summer water to dripline to help keep cool roots .. a maybe idea if room beside is plant another companion Ginkgo just in case your project one does not recover as hoped..