Joined: Jan 2010
Posts: 9,809
Likes: 1,784
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
Those stops are never easy to position precisely on both sides, so a single one is about as good as two imo.
I don't mind pushing the rim over a little with one knee while tightening the axle. Just keep some downward force on the saddle while the axle is tightened so the axle settles up consistently against the top side of the dropout slots and the rim thus centers between the brake pads.
If your bike has a claw-type derailer hanger, then no stop is needed (and left side optional).