I'm building a 9'-5 wt fly rod, and I'm trying to decide whether to put a second stripping guide on it. What do you guys usually do for a rod of similar size?

Just finished a Pac Bay which came with two stripping guides and fitted them both.
Hope this helps,
Phil.

Do you find that it increases your casting distance?

Will,
There is only one stripping guide on a rod. Typically you install one ceramic stripping guide and one more double foot ceramic guide with a smaller ring.
On a 5wt you might want the stripper to be #10. A #12 wouild be pushing it but you could use it. On a 5wt - the next guide could be a ceramic #8 or a large wire snake or wire singlefoot guide. Or you could use a #12 ceramic stripper and a #10 ceramic double foot guide. If you are building a 5wt rod for light saltwater use I would go with the two double foot guides - frest water - one double foot ceramic #10 and a ceramic #8.
The set-up that you use will not affect the casting.
Herb

Many fly rod builders now put a 'one or two size' ( smaller than the stripper) "Tamer" guide between the the stripper and the normal spaced second guide. They usually put this tamer approx. 4-41/2" from the stripper. Purpose is to help quickly 'tame' the large, fast moving big loop of fly line that first hits the stripper. I have tried it both ways and I very much like the casting results I get using a tamer.

Will,
I often add a second double footed guide (technically, only the butt guide is referred to as the "stripping guide", regardless of construction), as a "tamer". It is an extra guide, added about 4 inches up from the stripper. I find that it often adds distance, as it tends to keep the line from bunching up when I shoot it. Here's some info on tamers:[rodbuilding.org]

George Forster
Fort Collins, CO

Try test casting the rod with and without the tamer and see if you like it.

Bill - willierods.com