Offshoreonly.com - Switching from TRS to SSM questions

I know that the cutout for the SSM transom assembly is larger than the TRS. This winter I am going to redo my transom on my 377 Scarab. I'm also redoing the twin turbo engines and making them right with converting them to EFI. I have a very good pair of TRS drives on it now, and the engines should make 750 HP. I know that this is beyond the capabilities of the TRS but if I dial the boost down, the drives will survive. In the future when funds are available I want to convert to a pair of SSM 3 or 3A's. I know some people have filled the transom when converting from TRS to SSM. I'm just wondering if that is a bandaid fix until they can get a new transom installed. Like I said I don't have the funds to get this all done this winter and want to do the drive change later but I'm just concerned if this is a bad idea.