I also use YLI and the kicker is that my local sewing shop carries a lot of the basic colors in stock.
one spool is more than enough for a rod. on average you can probably get 3 rods out of a spool.
i like chestnut brown w/ black or Garnet and black
If you only need one spool and it's a basic color let me know. I may have enough to spare and save you some on shipping.
another place to try is goldenwitch.com. problem with only getting one spool is you end up spending more on shipping than the thread.
The only things we permanently keep, are those we give away-Waite Philips