The LT co might be easier for that many sts if you use 2 strands of yarn to CO with. One can be from another skein or the other end of the one you're working with, and use it for the thumb yarn, with the working yarn around the fingers. Knot the 2 ends together and just cast on. You'll have a couple extra ends to weave in when you're done, but can be a lot easier than trying to estimate how much yarn you need and casting on over and over if you guess wrong.
sue- knitting heretic