yeah you will need to readjust your carbs because some of the avaliable flow is taken up with oil and not with fuel but its stuff all
Mate i would trust Yamaha rather than a 30 year old doco. I'm sure they have a good R&D budget and came up with a safe answer, why fuck around and seize the ski for such a little gain in power.
The 50:1 has nothing to do with power but more with emissions if you feel your going to seize your engine running more oil and fuel then i suggest you need to look at your tunning methods more so than your oil ratios you can run what yamaha recomend thats fine and your engine will run just fine and you will have a smaller carbon footprint than the people who are enjoying the extra power of running more oil
32:1 thats nearly a running in mix. Im sure that you will find that the more oil you run the more your octane rating drops. Therefore less power.. I run at 50:1 its safe and doesn't fowl plugs.
The less ocatne you can run in your engine the more power it will make. Octane resists detonation and dosnt produce power. the only reason you would run a high ocatne fuel is if you have high compession.