The LongLow, bless its heart, is tight for fender clearance, even wearing JackBrown 33.33s. The zip-ties give optimal clearance, I don't think I had room for a fork crown fender daruma. The other tied points were the rear plastic tabs that the fender rods slip into, I zipped 'em to the rack tabs, and I'm also holding the rear fender's front clip (for the chainstay bridge) to the fender with a ziptie.
Pictures prove zip-ties can work, in a pinch. Or anytime at all...
https://www.flickr.com/photos/71141757@N02/15471603133- Andrew "just in time for dry weather," Berkeley