I don't think it would work to do 60, but give it a shot and let us know...
I gave it a shot... and you're right, it didn't change anything, just left it at the :30 setting. I didn't try it by toggling back to the "normal" operation and then trying the :60 setting.
However, there is a problem with setting your advance button to be a :30 advance. I was unable to find any method of advancing the program by more than 30 seconds after that -- no index advance, no advance to the end of the program, either in play or in fast forward mode. Not surprisingly, the advance button could not be fooled into backing up by 30 seconds.
Without the index-advance or end-of-program advance, the :30 advance is not too useful to me, although YMMV.
Neat hack, though!
tanstaafl.
_________________________
"There Ain't No Such Thing As A Free Lunch"