Power-Trac 421.667 upgrade questions

[agjones]

So I got some help from the forum on identifying an older pt. Compelling answers were given for it being a 418, 422, & 425. So I averaged them and will call it a pt421.667. Which is accurate enough since it's getting a predator 670 honda gx clone engine.

I'm now asking for help upgrading it some...

I'm replacing the hydraulic valve since one spool was seized, and adding a two spool valve to enable hydraulic qa and grapple on their own. I've ordered another hyd qa plate from the mother ship.

The pto is a manual handle, aimed squarely at my shin and loose enough to move on its own. To upgrade, I'd like to duplicate the switch/solenoid setup from my more modern 425. I have two questions about that :
1- can someone please link the right valve at surpluscenter.com?
2- what kind of plumbing would I need to add to let a pto attached motor/tool spin down (motor wind down) as opposed to sudden stop.
2b- would the plumbing recommended above offer some stall protection when a tool locks (EX rock in tiller, fence in brush cutter, impatience in stump grinder)

Thanks gang... Any other modernization I should do while I'm in this thing? Bluetooth tachometer is obvious.... So what else?