Hi, I'm no expert but I resealed mine last year using Jeff Grigg's method and it seems to be holding up. I would remove the inner plate since you're there already and it could be the problem.
The gaskets should be glossy with the thermo sealer; if not, send back and ask if in stock or order from a different vendor (both are sold under the same part number for some reason). All threads should be chased with a tap and bolts cleaned/replaced if worn.
I took the inner plate off mine and discovered a severe bend in it that was causing the water intrusion; it rocked back and forth when I placed it on the block. I sanded it down until it sat completely flat on the block using sandpaper on glass (would be faster with a table surface belt sander).
Clean all edges with acetone before installing. I installed the inner plate with an extremely thin coat of high temp RTV (NOT the copper kind) on both sides of the gasket, using torque specs and pattern with locktite blue.
My middle plate was also pitted and bent, I had to grab one from a donor motor that was in better shape. Even with a straight-ish plate, you need to ensure the middle plate isn't touching the inner diverter, otherwise it'll expand and push out at operating temp. Put a very thin film of grease along the length of the diverter on the inner plate and rest the middle plate on top without using any bolts. File or mill the middle plate until there is no grease transfer, and there is no light escaping between the plates.
Once milled and no light escaping around the middle plate, clean and install middle and outer plates with a very thin coat of black high temp RTV on the gaskets. I used locktite blue here as well. I don't have torque specs handy but they're in the manual.
Hope this helps.
