When is the best time for a trunk chop?

I need some advice please. If I wanted to purchase a Japanese Red Maple, when would be the best time to do a trunk chop? I would like to eventually end up with a 12"-16" tree with a good size trunk.

I'm planning my first chop this spring, so, I'm definitely a beginner.  I did find this article very helpful though.  This link is posted elsewhere on this site.  

https://www.evergreengardenworks.com/trunks.htm

There is also an article specifically on the Japanese red maple that I found interesting and you may want to read.  

Thanks.
Steve

Thanks for the info, Brent at Evergreen Garden Works is a good guy to work with.