What are the little spools I see in some of these kits? I have just the basic wrap line around a small bit of cardboard action going, those spools look much handier.
Bobbins are the easiest way to carry line. If you want to carry more line, here are a couple of different size bobbins for big sewing machines.
These are both about the same width, but they're about .05'' wider than your standard bobbin you get a WalMart.
This one holds about 150 feet of 35lbs test braided line, or about 60 feet of 80lbs test braided line. It's 1.087'' in diameter and about .46'' wide.
http://cgi.ebay.com/20-LARGE-SIZE-INDUSTRIAL-SEWING-BOBBINS-JUKI-LU-563-/390174928685?pt=LH_DefaultDomain_0
This one is about 1.45'' in diameter, and .51'' wide. It holds A LOT of 35lbs test braided line. I never actually measured it because it's just A LOT. It will hold about 100 - 125 feet of 100lbs test braided line which is a little thicker than the inner cords of 550 depending on the brand of braided line you use. I like this size of bigger bobbin for thicker cord than fishing line but not as thick as 550. I think that is a VERY handy size line to have in small kits, and this is a way to carry a lot of it cleanly.
http://cgi.ebay.com/6-BOBBINS-SINGER-144W-145W-CLASS-SEWING-MACHINES-/390066093601?pt=LH_DefaultDomain_0
When you wrap line around any bobbin, stick a small machine screw through the hole, and snug up a nut on the other side. Then chuck up the end of the screw in a cordless drill and wrap your bobbin on low speed. Take a coat hanger and cut it in the middle and hang your spool on the coat hanger and the coat hanger off of a nail or whatever. Now your spool of line can easily free spool and feed your bobbin with no twisting at all.
You can wrap A LOT of line evenly and without twisting it in under a minute. Use LOW speed because if the line slips off the spool, it wraps around your chuck FAST and it's a mess. Hit reverse to keep the twisting out of the line.