Right, let's take stock. We're looking for up to three items: a gear for the pump in J5, something (most likely a fuse) for the boxclaw in P6, and a wheel for the valve in Y3. There's also two doors, in I13 and V11. The door in I13 needs a key, while the one in V11 is linked to a '3' and a '4' pad (the '4' pad is slightly larger).

It looks like to continue we need to open the dome. It's not dependent on a 3:4 ratio of weight or pressure, as we've tried that (unless the weights need to be in an exact 3:4 ratio - I think I was a couple of pounds out). We've sort of tried numbers, but I'm not sure if the canoe counts.

There are also two small rocks, and a patch of light. Hmm...

Pick up the small rocks in F9 and U8, then weigh them on the scales at M15. Adjust valves as needed to actually make it there.