If you go 60:1 or 40:1 it probably wont hurt anything. Just smokes more or less. I ran my 1976 Johnson for years around 60:1. If it your main power such as a 1977 mercury jet, you probably run it fairly hard better take extra care to get the mixture real close.
I try to stay fairly accurate but more oil is better than not enough. Too lean may burn something up and too much oil and you foul a plug. I would rather clean up or change a spark plug. At least that is what I have always been told.
For me the proof is in the pudding. I asked a very successful Mercury service dealer what was the best mix to run in my new 2 stroke Kenai 40 horse. He advised somewhere between 75 and 100 to 1. I ran the motor without trouble for 5 years guiding under the hardest conditions they can be run. Slow backtrolling, running hard back upstream, slow backtrolling all day long. It smoked very little and ran great. The only reason I sold it was because I bought new, boat and 4 stroke motor. The guy who bought it from me followed the same routine and ran it three more years then sold it to buy a new Honda. It was still running strong.
I would rather run lean than rich because I don't like fouled plugs and dirty exhaust. It's just not that critical to be right on 50 to 1 if you want to run in that range.
Most oil bottles say 50:1 is 3oz per gallon. In reality, 2.56oz per gallon is 50:1. IMO (actual) 50:1 is the most you will ever need, unless you have an older engine that calls for more (they actually need it due to bearing design).
I've got buddies that run 12,000+rpm 2 strokes at oil ratios of 100:1 for hundreds of hours and never have an oil related issue.