Hops Infusion/Randall Best Practices & Recipes

Some friends of mine own a brewpub and have put me to task in finding a hops randall/infusion device. With that part of the task now out of the way, I'm now looking for success stories related to one of these contraptions actually in use. So here are some of my questions, hopefully someone out there can give me some feedback:

What hop varieties impart the most impressive flavor enhancement? Or should I just be creative?

Any experience with incorporating different spices or other ingredients to the randall for infusion? If so, what worked for you?

What types of commercial beers do you like to infuse?

What sort of commercial tap offerings would really make you jump out of your seat if you knew a randall was going to be utilized to enhance its characteristics?

I'd love to hear from anyone who has experience with using a randall or enjoys drinking/experimenting with infused draft offerings. Hope to hear some good stuff. Thanks in advance!

I have seen obviously hops, but also coffee for porter or stouts (even ipas now i guess). In terms of types, exotic or standard you probably couldn't go wrong with that.