The cotter pin retainer is really pretty practical. To remove, grab with channel locks and yank out. A slight rebend of the end, and a pinch with the fingers, and it will go back in easily. A little twist with a screw driver, and you are back in business.
At one time Wilwoods came with these cotter pins. Doesn't this model still?
The first Wilwoods made for 3.5" mounting centers in the late 1980s, and which would fit our 911 front struts with a little futzing with spacers between the caliper and mount to center things, came with four equal sized pistons. As a result, pad taper wear came on rather quickly.
Those Wilwoods had a reputation, whether deserved or not, of being flexy (like the S calipers did, I suppose).
I'm running an offshoot of the Wilwood called Bremtek (now many years out of business).
It has differential piston sizes top to bottom (with the rears being smaller) and has been very reliable. The seals, for instance, have run fine for about 15 years. I think the newer Wilwoods have this valuable differential.
In any case, the pads are a lot larger and thicker. I use pads sized for the Wilwood, so I am very glad they are still making and selling these. If your Wilwoods have differential piston sizes, I'd keep them. And work on getting rears with appropriate piston sizes. I don't think Wilwood makes a similar Ultralite with 3" mounting and smaller pistons, though it would be nice if they did because being able to use the same pads front and rear is really nice (the inner rears need their ears sawn off).
I didn't have to do much figuring with my Bremteks, as they came sized appropriately F/R for 911s and for a 19mm MC, plus I have a balance bar to adjust the bias. They work so well that I just went from two 0.75" MCs to a pair of 0.70s with no apparent loss of pedal (though not quite as much reduction in pedal effort as I was hoping to achieve).
I don't know what motor you have in that car, but I like the large pads (thickness I see you have dealt with by spacers) for my track only car, which is slowly getting below 2,000 lbs without me in it. I'd not want to go back to much smaller pads and heavier calipers. Nominally pad size doesn't count for instantaneous braking, but it sure seems to help in terms of longevity and heat while racing.
So, with all deference to those with other opinions, I think going to 3.2 brakes is a step in the wrong direction for a race car.