Sounds like a rather fiddly way to do it. And slightly wasteful of cable - for those who worry about such things. ;-)
I bought a 100m reel of 1.5 single green/yellow many many years ago just for this, and I'd expect it to see me out. ;-) But you can usually rescue some earth from cut-offs of the TW&E - and of course you will already have the sleeving.