Pretty simple actually if it works. Drill and thread a hole in the lid for return line (1/4"). Block off existing return line which is on the manifold. 3D print a pipe for the circulating flow to drop intake 1/4". Gas should build up towards the top and come out through the return without circulating through the reactor non-stop. Similar to the new design without the cost of getting the whole new system.
I bet they’d have parts to upgrade if you ask.