If any of the "coolant hose" you've bought isn't fabric reinforced don't use it... you're just going to end up making water balloons. I've seen a lot of crap kits pushing vacuum hose as coolant hose or trying to pass vinyl off as silicone (which then melts); There is a difference and it's much bigger in real life than it is on paper.
At any rate, I don't know of any reliable suppliers selling silicone hose for cooling applications smaller than 1" in diameter. If the company who made your kit is reliable I recommend you contact them; It shouldn't be a big deal for them to sell you a few inches of scrap.
No sooner than I speak do I find a link to a company who appears to have it:
http://www.sporthoses.com/parts/straight/