I got mine from the local pharmacy. I can't remember what I paid (probably too much), but do remember shipping being kinda steep.
Mine is 70% and the last batch I did, I cut it 6 to 1.
Which brings me to a question and I don't want to hijack Old Ford's original question but... Does it really matter what the ratio is? I ask that because if you add metal 'till it stops reacting, isn't it doing the same thing? Or is a more acidic ratio going have more iron in it? Hope that makes sense...
Ed