Assuming you are running balanced interconnects, you may want to consider the ARC CD-3 (cheapest), CD-3 Mk. II or CD-7 (most expensive). They are truly differential balanced and will allow you to take advantage of the balanced circuit in your Rowland rig. I ran a CD-3 with my Coherence II and I really liked it. The Coherence works fine with single-ended gear, too, however, so balanced should not be your most important criterium.
You may also want to consider contacting A-gon member and dealer Jtinn, who has a lot of experience with Rowland gear.
You may also want to consider contacting A-gon member and dealer Jtinn, who has a lot of experience with Rowland gear.