I think you are on the right track & well on your way to doing this yourself. Honestly you've already done most of the hard work.
I have a good idea of where I want to mount everything
That is the hardest part. Some of these partial kits (without hoses) still leave you to figure this out yourself so you save nothing buying those vs buying the components yourself other than the time to source them all out - which you have already done.
I went into
surplus center and put together what I believe to be a complete kit with valve, subplate, all hose fittings, hoses, and flat face couplers. The total with shipping comes to $318.96. ... the total is as close an estimate as I can come up with.
I originally went to school to be an engineer so stuff makes more sense to me when I can draw it or list it out rather than just trying to see it in my head so I threw together a quick n dirty spread sheet for you listing the basic components - you'll have to fill in the specifics like what size fittings & hoses, thread callouts, etc but it's a component by component list of all the parts you should need.
Almost all your quick couplers have NPT threads so it's up to you to decide if you want NPT ends on the hoses they connect to or if you want JIC ends and JIC to NPT adapters but I will say that (with the exception of my loader arm hoses that have QC's on both ends) I wish I had gone with JIC everywhere in my project. It would have made some things a lot easier and in some cases cheaper too.
If I can get the wiring aspect nailed down then the custom kit it is ...
It's actually not as bad as you think. (I know one of my favorite sayings is "Brain Surgery is easy when you know how to do it")
The solenoid will have 3 terminals - Function A Positive. Function B Positive, and Ground
The control switch should have 3 wires - Positive In (Center of switch), Button A out, and Button B out.
From your power source (Battery, fuse box, whatever) go to the center of the switch,
then A out on switch goes to Function A on solenoid,
B out on switch goes to Function B on solenoid,
then Ground the Solenoid to the chassis.
Done.
Be sure to add fusing if you're not using an already protected circuit, and another idea I liked that I "borrowed" from another members build, is adding a simple toggle switch in the power circuit before the control switch so I could turn off the 3rd function. This is an extra safety so I don't accidentally activate the solenoid when nothing is attached and dead head the hydraulics. An idiot switch if you will.
When you take it bit by bit, it really is a pretty simple project and you should be able to do it just fine.
Besides - you have tons of help & resources here if you get stuck.
