Absolutely this is helpful. This is exactly the type of breakdown I'm seeking.

Doesn't significant throttling loss occur with high vacuum? Will a gain there be noticeable.

Mitsubishi is demonstrating GDI engines now (Gas direct injection) that do not use a throttle plate, except as required by DOT safety regulations, as I understand it.

So we have these offsetting penalties:
Running lean/open vs. lowest total charge
Peak torque vs. lowest friction
Throttling loss vs. excessive lean condition (detonation)

My initial question was specifically asking about asymptomatic detonation.

Am I risking anything by continuing to lean down, if I don't hear pinging or see the temp gauge rise? Just for experimentation, to find the right balance between perf and economy, using only stock systems.

I'll decide on some sort of metering once I get these baselines. Right now I'm leaning toward fuel pressure vs. EGT.
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'74 145e T-5 'Orange Alert'