i have the 14.5 bigger boy.
first off - ferment till its done - most of my lager ferments are 10-12 days tops, but be sure its done first. don't assign an arbitrary time - the worst thing, esp with lagers, is to remove the yeast before its finished cleaning up after itself.
second, harvest the slurry in a mason jar or other similar container, keep in the fridge and if you don't use it within 2 weeks THEN make a starter a few days out before your next brew (give yourself ample time to ferment and decant).
third, you don't really have to collect the day before - there won't be all that much beer to decant when collecting from a conical- I often rack to kegs while I'm brewing the next batch. unless you were say, making a pilsner with yeast harvested with a dunkel, then I can see some validity to that.
fourth, make sure you are pitching the proper amount - don't use the whole thing. www.mrmalty.com
hope that helps - I think I covered all the bases - if I think of anymore, I'll post back...