Dal, there are obviously many routes to take here on holding the truck from pushing thru the brakes. I would include input on one thing for you whether or not you take it or leave it:
You don't want the truck using the rear brakes to stage in order to not push thru. Why? When your sitting there at the line holding the brake to launch, the entire chassis of your truck has a load on it, a twisting load, from your flywheel, thru the driveshaft, the axles, and an overall incorrect stance for launch. Where as a transbrake type set up is loading only the "transmission". The pinion brake is absolutely ideal in my opinion as well as "bang for your buck" since I know you have a budget to work on like everyone does. Then later if you throw in a looser converter, try that.
Now on the converter choices:
I dont know what you use for data logging or if you use anything at all. Data logging of any kind is the only way to keep moving forward. When selecting the right converter, what do you shoot for?: spoolablilty? acceleration? combination of both? Now sure you can throw in a looser converter to spool better and hold the truck, but if the converter "flat lines" down the track, it's too loose. I dont know your set up you have now but there may or may not be room for looser. By flat lining I mean, laying on the converter. When you lay on the converter and review your logged data, the drive shaft ramp should closely follow the engine rpm ramp, if it quits accelerating and rpms are still high, converter is too loose.
I'm not just incredibly familiar with the Ford tranny set ups but here is something you might take some time to research that might work. In order to run a tight converter and still spool it, there is a little something called a proc device. How it works is by the push of a button (usually transbrake) it pulls fluid from the converter to make it spool or rev faster, at the release of the button, it pushes the fluid back into the converter leaving it the tight, accelerating converter you want. As far as this goes, it might not even be possible to use this application on your tranny as I don't really know Ford tranny set ups incredibly well.
You might know all of this already or you might not. I just thought I'd try to lend a 100th opinion like I said whether you use it or not.
Anyway, good luck finding the right combination!
