Dan Craft Sig V 9' 5 weight question?

I'm getting ready to build up this rod. This will be my second Dan Craft Blank and so far I'm nothing but impressed. My quetion is has anybody tried a 4 weight line on this rod? I'm curious if it would still load it and give it a bit more speed for fast casing strokes (impatience)?
Let me know if you've tried anything,