From your reply I gather you have a Thick Flash.

From experience I can tell, the Thick Flash is very stable, floating upside down, my son once flipped his boat shortly after the start (due to a ESC malfunction that kept the motor running at full throttle) and it floated with a sreaming motor for the entire length of the heat...
Even the waves from the other boats tearing by wouldn't turn it back up.

So we mounted a floodchamber and have had no problems with self righting whatsoever since.

As you can see in the pic, the twelve cells are distributed equal, my guess is, that with a 8-6 cell configuration, the eight cell pack on the left side, the boat will turn back up after a flip.
If it remains a problem, I have a template for the floodchamber wall...

Here are some pics of the Thick Flash.
The runpad end can be seen at the rear view, it extends all the way up to the step, as seen on the bottom pic of my Yellow Flash.

And yes, we are happy with this boat, even it's an older design, it handles chop much better than the newer flatter designs, which are quicker, but can't make it count in races, specially in rough conditions, as they spend more time upside down that running, than our slightly slower Flashes.
My son was Dutch champion in 2005.

We had our problems making the Flash turn at speed, without flipping it, the position of the turnfin wasn't to our likings, mounted at the transom.
As an experiment we mounted a plate, as shown in the sketch on the right hand side of the hull.
The 'turning plate' is much more shallow and barelt touches the water, running straight (=less drag), when the boat banks into a turn, the fin gets hold and does it's job very well.

Showing up at the races with this turnfin for the first time, we were laughed at.
After a few races most competitors have copied our idea...

Let me know if you have more questions.

Regards, Jan.