Dear ryguyfi,
I tie the green weenie with the loop tail. I also tie them with a beadhead most of the time. Try them in red, they are called "red hots."
As far as the length of the pink worm, trout have no problem eating an earthworm or a nightcrawler so they have no problem eating an IPW.
In case anyone is wondering, I've never had one "swallow" the IPW and wind up gut hooked. It's a great fly and one that I won't go fishing without.
Regards,
Tim Murphy 🙂