Good score, Chinese Quince make fantastic bonsai, and they're not common, despite how easy they are to propagate, and how fast they grow. Some general observations from growing a bunch in the ground:
1. New shoots grow in canes (rose family) and bolt upright very quickly and with almost no taper. If you're keeping it in a bonsai pot, wire the branches early to get shape, and exaggerate the movement to ensure it doesn't grow through it in a few years.
2. If you're keeping it the pot, cover up those surface roots with a little sphagnum moss so they'll continue to thicken. That will also improve the base by thickening some of the thinner roots. if you do want to grow it strong, set it on the ground and let it escape. Even in OH, you'd likely get 6' of growth in a season... worth about 1/2" of caliber.
3. They seem to have thin bark and thick cambium. If you prune the trunks back, try to keep the cuts to the back and quite concave, or it will develop a bulge around the scar. Surprisingly, as fast as they grow, they close wounds relatively slowly.
4. New growth is STICKY, and aphids LOVE it, maybe because it's such an early starter. Be vigilant, although they don't seem to do much damage.
5. They start growing the second it's above 40 degrees outside, and late frosts/freezes do not harm the opening buds; that only slows them down for a few minutes! They'll have red fall color on last year's leaves, and new buds opening at the same time in this climate. Wherever you're keeping it, make sure it has the benefit of as much sun as you can provide.
Keep the updates coming!
