Surely the problem with the proposed standard does not lie with Slaters, but with the rest of the G3 modelling crowd? slaters produce wheels to the current standard measurements, if we all said we preferred a different standard they would produce wheels to that one. It makes no difference to their machinery, the tolerances are the same, aren't they? the problem is the migration from old to new. Would that mean tearing up and throwing away existing track? And if new track were needed, could existing wheels cope with it.
The earlier post says we would need to replace track, well I've just replaced £400 of GRS track with £300 of Cliff Barker(a simpler layout) and would need to pay someone to upgrade the latter to the new standard. And then there's the cost of converting stock.
The tapered axle is a very different problem, because it means extra work in the manufacture of the axle, and therefore extra cost. I would have thought someone could earn himself some beer money offering a tapering service, tapering existing Slaters axles.
One final question, but an important one, what are the minimum curves for the new standard? I've upgraded from 8' to 3m. Could I get a 4F with the new back-to-back round 3m curves?
I think you should go ahead with your new standard, but you need to build a small layout to take to exhibitions to show everyone how much better it looks and build from there. That's what the EM, P4, and S7 guys did.