I'm afraid my theory knowldege is practically non existent so you're impressing the hell out of me with talk of diminished thirds! Basically i get a piece on tab,listen to how it should be played and then proceed to murder it repeatedly.
However,if you can help... the tab I'm working off is http://www.classtab.org/ftacap_a.txt
and its the part in the 15th and 16th bars that are freaking me out.Any other source of tab on this may help.Not convinced it's right although I'm probably doing the transcriber a serious injustice.
Thanks again!