this is what most would do, until they find out that the heatshrink cant slip over 3 ends of the wire. your best bet is to heatshrink all wires so that it's as close to the T area where it's soldered, and get it real close. Then fold the hanging wire carefully back against the main wire, and then heat shrink it tightly with a larger guage heatshrink, then you can curve it back to the injectors, carefully, so that you don't stretch the shrunken heatshrink to the point where it cracks.
and make sure that if you're using copper wire (most would), that you don't heat it too much or use a soldering iron that is more than 15 - 20 watts, as you will heat up the copper and crystalize it, so that it snaps when you bend it (which you sort of have to do)
I'm wondering if any electrical place has small snap-in plastic T-wired covers, so that you can snap them over a nicely soldered T, and then heatshrink up to the ends of the T, to seal them.
But they'd have to be thin so that they are nice to look at, or not look at, which would be the point in making it unnoticeable.