Joined: Aug 2010
Posts: 12,727
Likes: 2,105
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
In the past I have cut plastic fenders to fit. But, if I was installing some nice metal ones like you have, I would start with the L bracket and not cut them. If I was unhappy with the results, you can always cut them later. But once cut, you can't uncut them very easily.