Well, in trying to figure out the best configuration based on everyone's experiences, I contacted Protech to request fronts at 14" x 250lb and rears at 12" x 225lb, and was told this is what I'll get instead:
400 series 2.25” id Front 400mm open (15.75”?) with 10” x 300lbs springs. Rear 464mm open (18.25”) with 12” x 250lbs springs
So, 10" x 300lb and 12" x 250lb... This setup is exactly what Richard was given last month and the front ones weren't right. I advised Tim (at Protech) of this, and of his discussion with Terry and Dave (referenced in Slice 293), and of Dennis' collaboration with Protech, all confirming that these figures don't work, but I have received no response since.
I never imagined there'd be such a range of opinion. There doesn't appear to be an 'agreed' spring length and force. It's a complete shot in the dark, as either nobody knows or nobody can express it with clarity. I might just stay put with the standard springs after all, because whatever I order is likely to be problematic in some way or other. Hmph... Moan over.