Cortland Mini-head

I bought a Cortland Mini-head sink tip (6 inch per sec sink rate) and pairing it with 6 wt line to fill a spare reel. My intent is fish streamers if the opportunity presents itself. The mini-head is 12 foot long, but I believe it is to be shorter. I will be fishing small-medium streams in central and NE Pa so long casts should not be an issue. Without too much thought on current and depth, what length would you cut the mini-head to for your average trout steam to get the streamer down a few feet? Also thoughts on the set up for deep nymphing? Thanks.