The only differences between the Kubota timer and New Holland's is the length of the glow and price. The contacts and electrical connections are identical. The NH timer is designed for fast heating glow plugs and has a 5-7 second cycle. I think the Kubota cycle is 10 seconds. . . no big deal. I have two Kubota's for spares, but have not tried them, but others have successfully substituted them. The timer does not supply current directly to the glow plugs on our tractors. It only energizes the high current relay.
BTW: Kubota charges over $60 for that relay at a dealer. It just goes to show you what a markup there is on these parts. I have replaced $75 relays on my NH TLB with a $9 part from Grainger that is an exact duplicate except for mounting. My cheap relay came with a tab for mounting with a screw. Otherwise, there is no difference. Evidently there was some excess Kubota inventory that ended up on eBay. I found glow plug timers for just over $10 each and that included shipping. The Kubota kit even comes with a glow plug lamp, but of course, you have no use for that on the New Holland. It also comes with mating connectors and contacts. It's one heck of a deal. The next time I have my cowling off, I'm gonna swap out the relay just to test it, but I can see no electrical difference between the two.