[VFB] Leader Construction question(s)

[Peter Gramp]

Hi, everyone!  I was out fishing for all of 30 minutes last night (it got dark in a moment, and my light burnt out...) and got frustrated with how fast I go through tapered leaders.  SO!  I thought I would try my hand at blood- knotting the way from the line to the fly.  Herein lies the problem:  I have tippet from size 3x down to 6x, usually used on the end of a tapered leader, but for anything larger than 0x, I can't seem to locate anything.  The leader formulas I have call for up to 0.022" diameter tippet, which is twice the thickness of the 0X I have access to at the local shop.  Am I using the wrong formulas, or is this a 3/0 X or a wire or...?  Can someone help me with what I need (I use a cheap-o 5/6 wt rod that casts a 5wt line beautifully, usually with sizes 12-16 flies, if that helps) and where to buy it "a la carte" (100US$ is pricey for a whole "kit", and I can whip out a blood knot in no time flat)
Any help would be great!  Thanks a ton and tight wraps/ lines,
Pete