Low/Reverse Piston

My Low/Revers piston doesn't have the check ball. What advantages would there be to finding one with the check ball if any for my re-build? I'm trying to follow Frank's build sheet as closely as possible!

From what I know/think, it'll help the piston potentially release faster when its turned off, basically a bleed. I just drilled a .030 hole for the same effect. I've also ran them with no hole, no problems with them as of yet. These are on non AND transbrake apps.

I've never laid eyes on one of these old style pistons... Do you know if there are any dimensional differences besides the checkball.. Such as height?

Just me thinking here--- I would prefer the circuit without a bleed hole... Seems like the checkball/ added bleed hole would just lower the apply pressure and potentially make it easier to slip the clutch??

From what I've seen, all low-reverse pistons interchange. But the hole and retainers can be different. As far as the bleed, there is more than enough oil back there to apply the clutch. It's not a 1" hole, just a controlled bleed to help the piston return when feed oil is lost. I've run them both ways, but with the hole makes me feel better in a scenario where the clutch is applied in manual low, and needs to overlap with the band on a 1-2 shift. 
My .02

The new style piston ie; with no check ball is shorter so you have to use the wave plate in the low/reverse
Frank