stewartia trees

Hey all! I purchased this Japanese Stewardia over the weekend. It’s around 60” from the root base to the apex. The trunk above the taper is spring 2” thick. Would it make sense to airlayer to shorten the main trunk or just lower the apex and keep it long and slender?

I have had trouble growing small Stewartia trees for bonsai. I am using large containers with good draining soil. However the last two years only one has taken off. The other two just stand with just 1 or 2 leaves.. I cannot tell the variety as the small leaves are tiny. The other is growing...