I have a leg length difference of about 5mm, and I am very right-side dominant. Right side is also the longer leg.
My R/L power split difference can be as much as 60/40 if I'm just idling along and not paying attention to form. However, when I am putting the hammer down on climbing intervals it is much closer to 50/50 sometimes even going 48/52.
I've just had a bike fit done with Aaron Dunford at Fairlight who did some Steve Hogg voodoo with magnets and muscle proprioception testing, and I now have some shims and wedges, especially under my left cleat. I've only done two rides since the fit and my pedalling certainly isn't any worse and I feel a whole lot more stable and planted on the bike despite the saddle being 6mm higher.
After seeing the comments above it will be interesting to check the stats on the Garmin and see what the average split was for yesterday's gravel grind in Yass and see if the shoe changes have made any difference.
Anyway, good luck with the journey Michael. I've just bought a copy of Coggan's book. I'd better go break the cellophane
Was just advised by the mob that they don’t ship PM’s internationally any more, as if there are issues, too costly to resolve and not being able too easily test S/H PM’s easilybprior to shipping. So back to square 1 again, almost. 
Unless I didn't get it right.
