Ironpen, you need to be sure of what you want before you start. You said you wanted one remote for a hydraulic toplink. If that is all you want and you'll never add other hydraulics, then go with the New Holland kit and be done with it is my suggestion. The prices of adding a remote setup you build for yourself have to include building mounting brackets, hoses and rigid tubing, quick connects, and routing all your own lines. If you buy the NH kit, it includes everything you need to put a remote valve and lever on the right side near the 3PH control. It will come with rigid plumbed lines and mounting including quick connects that are right beside where your toplink attaches to the tractor. You'll only have to buy the hydraulic toplink and two short 1/4" hoses, probably around 36" long adapted to two male 1/2" quick connects using reducer fittings. You won't have to cut, weld, drill, or plumb lines after figuring out all the fittings you need. If you are a hydraulics expert, doing the kit for yourself is fairly easy, but if you are not an expert and don't have building skills, then it is a daunting task to get those after market remotes added. It makes it even harder that you do not have a loader. I think after you've spent the money for the NH kit, you'll be happy you did it.
Oh yes. . . if you go with the NH kit and decide to add other remotes or a loader, your NH kit will remain in place without modification and with easy add-on of other components. If you build your own setup and later add a loader, you'll be back to doing plumbing and re-routing lines.