So maybe FastClick should be disabled for these browser versions.
PS: I had some bugs when using FastClick with Firefox 34 so a fix might be neccessary. If you do not want to add Firefox to the ignore list, I will open a new issue with the bugs I had
Firefox for Android removed the 300 ms click delay in version 30. (https://bugzilla.mozilla.org/show_bug.cgi?id=941995)
I tested the delay with http://ftlabs.github.io/fastclick/examples/layer.html. With Firefox for Android versions 30 and up the remaining delay is negligible (5-10 ms).
So maybe FastClick should be disabled for these browser versions.
PS: I had some bugs when using FastClick with Firefox 34 so a fix might be neccessary. If you do not want to add Firefox to the ignore list, I will open a new issue with the bugs I had