More to think about, I have had chains "profesionally" ground. YUP, burnt and blue.
I have used the clamp on guide, nice, but if you don't have everything set right, you can't "feel" if you are messing the chain up more, or doing it right.
Useing the deal that clamps on the file caused me more grief than anything. The files don't seem to go as deep as needed.
Try hand filing again. It's easier on 3/8"s chain, without a chain all rocked out. You can get the feel of where the file should be and the right angle. A rocked out chain, yeah thats tough to start. Once you get it you wont be as hard on chains either. It's easy to file a dull chain, it's a bear on rocked chains!!
I can do 32" loops in a half hour or so.
I can't set up and grind one that fast.