lots and lots of patience. mate box can be really slow growers when the roots are confined in small pots. get it into the ground or a grow box and feed heavily in a few weeks and keep it going for the next couple of years. allow low branching to grow and extend as sacrificial branching. this will help thicken the base up somewhat.
let it grow freely but always keep in mind of how it is growing.
good luck
SHOHIN YAKUZA!!! taking the top half of trees of since 2005!
and growing trees for the future generations! 50+ year plans