Looking for rubber strap watch.. Was originally interested in the AP ROO 15720 but these Panerai models have caught my eye and I do favor VSF, particularly the 42mm 1579 or 1565, or the 40mm 1408. I get the thickness isn't very accurate, and maybe too inaccurate on the 40mm, but more importantly what's this I hear about a fish-eye effect on the crystal, is it that bad? I've read people 'swap crystals', however I'm very novice with this so I'm more about just wearing it as it is.