I have a line of credit from chuck schwab @ prime - 0.51%, which is current @ 3.49%. I'm not sure I'd be able to do this, but I want to lock in at this rate, I'd long a futures contract of interest rates, but how do I do that?
Why don't you call Schwab first and ask if you can pay a small lock fee to lock the rate? Most HELOCS are set up that way.