we use the connector from JTL for an older PS version, we are now using Thirtybees 1.5.1
you can use it to collect shop orders, that's enough for us.
the shop does all the item management and warehouse management, not JTL Wawi (note - Wawi is usually the boss and transfers everything to the shop!!)
as I said, that's OK for us, but we get an error message when collecting the orders, after we collect them again everything works.
so if you're thinking about having the connector adjusted, we'd be there, even financially 🙂