On my backup Hydra-Matic transmission, someone used a spare shim between the ball seat and the extension/tail housing.
They first put the rubber O-ring in the groove, then put in a spare shim, then the ball seat.
Didn't see any adhesive and can't tell you if it worked because the transmission was out of the truck when I picked it up.

The outline of the ball seat matches the outline of the powerglide rear tail.
The outline of the extension/tail housing of the Hydra-Matic is slightly different than the outline of the ball seat.
They use the same ball seat on both the powerglide and the Hydra-Matic.
Between two of the six holes on the ball seat there is extra steel.
You can place the extra steel facing up or down on the Hydra-Matic extension/tail housing.
The ball seat will only lineup oneway on the powerglide.

Logic dictates when placing the ball seat onto the Hydra-Matic extension/tail housing. .
Place the extra steel towards the bottom side of the extension/tail housing, which may impede oil from leaking.

Another thing a person could do is slightly bend the ball seat bolt hole tabs away from the extension/tail housing.
When you tighten the bolts, the tabs will flatten out, and the inner portion of the ball seat will apply more pressure onto the rubber O-ring.
Which may create a leak free seal.

1954 Chevrolet 3105 Deluxe Panel Truck
w/Factory HYDRA-MATIC