You can use pretty substantial fenders with the long reach NR brakes. Haven't measured them, but here is my early 70's Falcon San Remo on the CR website with NR brakes and some pretty hefty steel mudguards. No problems with this setup, though these may be about the widest mudguards that would work well.
Big Spring, Texas, USA
> From: KRISTER KATSOGIANNOS <email@example.com>
\r?\n> Subject: [CR] fenders and campagnolo NR long reach brakes
\r?\n> To: "classicrenezvous" <firstname.lastname@example.org>
\r?\n> Date: Monday, February 2, 2009, 11:00 PM
\r?\n> I would like to get some input on what size fenders the long
\r?\n> (normal reach) nuovo record brakes can be used with on 700c
\r?\n> wheels .
\r?\n> I don't know if its common with rubbing of the brake
\r?\n> against the fender
\r?\n> while braking and it would be nice if that could be avoided
\r?\n> Krister Katsogiannos
\r?\n> San Antonio TX