The gauges look like they have wire on them, just not much of it. So why don't you use wire the same thickness and as far as fuses go you most probably wont need more then a 7.5 - 10 amp. Either buy inline fuse holders or cut the cable and crimp a spade terminal on each end and each blade on the fuse can go in the spade. Cable tie and a bit of insulating tape, jobs a goodan. It's deciding where you are going to take you feed from that may be tricky. And as far as T piece goes, you would still have to cut the wire to add such a thing on. If you want to attach a wire to an existing wire without cutting it you would have to use Scotchlocks but they are a bit messy. You cant beat Soldering. It's really not that difficult to solder something, you just sometimes need an extra pair of hands.
Heres a link for some good connectors, fuse holders, wire etc
http://www.kojaycat.com/ They have an ebay store as well. I'm pretty sure if you give them a call they would be able to advice. Looks like a small family run business and they are into their bikes as they have made wiring diagrams for them.
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