Okay, string spacing was never something I thought about until my recent renewed interest in learning how to play a bass like a bass player. I'm looking to order a NordyMute and was like, "wait, all 4 string basses aren't the same?" Forgive my ignorance. I proceeded to break out the old ruler and measure the string spacing on my '13 MIJ 60s RI Mustang. 17.5mm! Umm... Nordy has mutes on their site for 18, 19 and 20mm spacing. From looking at specs of other basses, these seem to be the common spacings. I did a search online and bestbassgear.com sells them in all different sizes, including 17.5mm, but they're on backorder for months. Two questions... 1. Can I use the 18mm? 2. Is this 17.5mm string spacing some weird vintage spec that they "faithfully recreated"? Any Fender gurus know?