I have a 9 foot Sage xi2, 6 wt. I use it primarily for saltwater speckled trout. Im going to Montana this summer and would like to line it up for Spey casting. Can you recommend a set up for me?

I would use the OPST Commando Smooth, its whats called an integrated line which makes it easier to strip flies back in after swinging them in current. I would use a 250 Grain head on that rod and use 7.5' OPST Commando Sink tips in various rates. Here is a link to the line, and it must be used with some type of tip just FYI - Good luck! https://redsflyfishing.com/products/opst-commando-smooth-integrated

That sounds like fun, but, I have never fished using that method. Sorry