I installed this plugin the other day for the 1st time and thought I'd feedback a couple of things.
There looks to be a problem with the installation instructions on WP.org as they appear to suddenly end - does this need correcting? It would be nice if it stated where the settings screen is as it wasn't initially obvious.
Secondly, I found that the Tab Order field had been initially populated with an invalid value - I didn't note it down before I corrected it, but it appeared to be a variable name. I'm wondering if you've accidentally assigned a variable name, rather than value, to the field by mistake.
Lastly, it's desperately after some further instructions, particularly on the fields in the options screen, as I don't think it's always obvious what requires entering. This could either be additional information on the README or a drop-down Help on the screen itself.
I hope this helps,