Just taking a quick glance through the script, it looks exceedingly well-written. The complexity, I think, comes from the fact that it's very long and it doesn't sound like you're very familiar with long-ish scripts. The one major thing I'd do with this script, if handed it, would be to put a bunch of stuff in modules, but that's not a biggie.

As for redirecting back to the same page ... that's essentially just displaying the same page, right? So, create a function (or use one if already created) called something like &display_page_with_choices() and call it if you have nothing in %params. You make that check as soon as possible.

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.