Bet this goes on for many pages

This Forum is a great way of gaining information, the benefit of experience & expressing opinion.
There is no finite answer to the original question & my own intention is not to cloud the waters but perhaps make readers think through the real reasons they adopt their habits with regards to oil mixes.
Contained in this very thread are examples of what type of oil, the manufacturer & the mix ratio.
Besides that, there are examples of the ratios that some would advocate not necessarily based upon the state of tune, but on the capacity. Why should a 225, say, need more oil than a 150 in a similar state of tune?
I would consider that any engine set up to the optimum, specifically bore gap, squish, cooling, plug type as well as ignition timing & carburetion is probably no more likely to need a better quality of oil, or more of it, than a bog standard engine in identical theoretical circumstances, say, a continuous 56 mph for 200 miles.
However, we all tend to accept that with an engine modified to deliver more performance, there will be the need to consider better quality oil & more of it.
Yet, given the inevitability of the modified engine using more fuel when driven harder, there will be more oil delivered in the process.
To put things into, hopefully, a better perspective, I am aware of even air cooled RM250’s that race on 40:1 or leaner.
I don’t know what the best oil & ratio are for a given state of tune, but I reckon that most of us probably err too far on the side of caution, much as we have the condition of ‘LambrettaClutchHand’
When you consider how many still shut off going downhill, which is a fairly severe test for any oil, how many are likely to have seized?
So, my question is can anybody state categorically an oil type & mix ratio that let them down & how? If so, what did they adopt in the future as the cure?
Presumably we all stand to gain from the shared knowledge……
