transom support

I have a 22 inboard and I am in the process of installing a 9.9 auxillary engine(90 lbs) on a new garelick outboard 4 stroke bracket. The bracket is very beefy but I was hoping for some input on the ability of the transom to handle the stress. The boat is a 79 chris craft CC so it is well built, The transom has a convex shape and at a slight angle and is 3/8 - 1/2 solid glass. Since the boat has much needed trim tabs, the bracket is going to have to be mounted near the center which has a little more flex than I thought it would. I have mounted the bracket with a 1/2 marine ply backing plate.

Any thoughts as to whether the transom should be able to handle the load of a 9.9 in any type of condition?

Thanks,

James