What type of EFI is running this engine? Is it using a Alhpa-N (throtttle position) strategy or Speed Density (MAP) strategy? With the velocity stacks, I doubt you are using Mass Flow.
The reason I ask is that I have gotten help from a fellow in Louisiana that has designed an EFI system that was capable of more than I can tell you. It can do Alpha-n and speed density, too, but it is also capable of running 8 Mass Flow sensors and 8 O2 sensors for true individual cylinder control, for certain. It was developed or marketed to a marine engine builder. I'm pretty sure it was more than 8 cylinder, but not sure if it was 12. Since 10 cylinders are not common, it was likely 12.
This guy is a gear head, car guy, and more interested in helping fellow gear heads than most people you ever meet. When I talked to him about it. He said he was definitely thinking about solving all the problems with 8 stack EFI systems as he was designing it. I am sure he would love to put one on your engine and would work hard to make your engine run perfect. The cost was real close to other EFI system you can buy, if memory serves me. Of course if you did go 12 Mass Flow and 12 O2 sensors, you would have a lot of money in sensors, but you wouldn't have to go that route.
Here is a link to a Post of mine on this subject back when I talked to him last. It has his phone number, if interested.
8 Stack EFI New ECU Option Offer