You can learn a whole lot at a regatta!
If there is some other sailor/competitor there with the same board, approx. same sailor size and rig size, check out there they have their mast foot positioned.
I'll be very surprised if it's all the way forward (unless it's a full on formula board in really powered to overpowered conditions).
You won't be able to match a formula board with your 9.8 and the F-Type, even if you try very hard.
The formula board will have a larger rig/fin and is designed to go really high upwind and really low/deep off the wind.
The F-type won't go as high or fast and won't go as low and stay on plane due to the design of the board.
If your regatta course has more reaching marks than upwind/downwind marks you might have a slight chance to hang with the formula boards.
Since you only have limited distance you can go on your small round lake, you won't have much advantage over the longboards in the fleet unless they choose to short tack straight up to the windward mark.
Try the mast foot back at least to the middle and see if your board doesn't plane sooner.
I think you'll find another "gear" to your boards.
You've been holding your boards in 4th gear (with the mast foot so far forward) but they both came equipped with 5 speed gearboxes so you need to shift into that higher gear and really take off.
Nicest thing about a regatta is that you start with the rest of the fleet and you can watch/imitate what the faster sailors do and learn alot in a short amount of time.
If you see someone who usually places at the top of the fleet and on a similar type of board and rig, get behind them and follow their every move. See how long you can hang with them.
Strategy is important, but it only applies if the faster sailor is on similar equipment.
Don't do like I once did and follow the longboards off the wind (I was on a Formula 155).
They cruised along in displacement mode and I followed when I should have been sailing my own race and stayed planing at much higher speed to reach the finish line sooner but having traveled a greater distance.
Hope this helps,