Hi Frank, yes I see what you mean. The problem with what you have is that the loads acting on the suspension mount will be mainly carried by the small square tubes at the top. Somehow a way needs to be found to carry them down into the main part of the chassis.
I think that the solid piece needs to be replaced with a piece of box section. This probably means that first you have to reverse the bolt on the top suspension arm and put the captive nut on the other side.
The replacement box section can then go down to the top face of the main chassis member.
See if you can do something like this. Sorry for making it difficult for you but I really think this is necessary.
Dave