Henko,
I did my first valve adjust about 2 months ago with only the .004" feeler gauge. I read about the "backside method" but I did not have the proper gauges and was itching to give it a try.
http://forums.pelicanparts.com/showthread.php?threadid=264722
My results were like yours. Better running but still noisey. I got my .0025 and .003 and went back in.
The results of my first adjust (measuring the backside) was:
7- loose
2- tight
3- O.K.
The backside method is brilliant. I don't see how you can make a mistake using this method. It took me a full day but my car runs better now than in the 18 years I have owned it.
I found some 12" long individual feeler gauges (as well as short ones) that came in handy. lespaul's tip on removing surrounding engine tin sounds like a great idea.
Good luck,
Jeff