some ideas for you to consider with your quince. Next repot let's get it into a round pot, so as your developing it's branching you can face it for viewing easily with a simple turn. I think a nice contrasting color would help. Suggest blue or white. Most ripening fruit is a greenish yellow.
Tho many of my quinces are cascade, I'd like to see you focus on allowing your branching to get some diameter before cutting back. I have fewer single trunks in my collection as I prefer
kabudachi or clump style.
It's the natural way quince grow, so if you want single trunk stay on those shoots appearing
from the ground and remove them quickly.
As your design evolves over time, try not to be tempted to switch to clump style, as ofter
your former main trunk weakens and you may loose it,
Developing fruit also is a strength weakener, so limit the ones allowed to develop to maybe one or two.
I work my soil to have a tad more organic in it as quince seem to like a bit more moisture
then many of my other trees.