David, I simply used the new form of Slaters insulated bearings on my A1 tender.
To save you wading through my long and convoluted thread, I'll post the relevant photos here if you don't mind and some notes.
View from above showing slots cut in the inner frames and the CSB wire running over the top of the bearings, I know it's not the accepted pin point fulcrum points but it works, rather well surprisingly.
View from below, the objective of the trial exercise was simply to get the easiest and simplest form of pick up and suspension I could.
Next a strip of double sided copper clad was added, on the lower surface it's soldered to the brake hanger rods, small holes were drilled and the cable from the insulated horn blocks fed through and soldered on top. At the moment I am not running split axles so only two axles are live on each side, as noted above it's all trying to keep it simple, if I have problems then I'll employ split axles, but if it all works fine then I don't need split axles and that's a task saved.
View from below, don't worry about the soldered tab top left, that's my mistake in tinning for the brake rod fixing, the cable is still insulated as it passes through that area to be soldered on top.
Close up of the insulated bearing and the pig tail for the cable, it's quite a firm cable so the bends allow it to flex easier with the suspension, you can just see the epoxy glue bonding the cable to the bearing housing. You can also see the thin slot in the rear of the wheel with wire shorting rim to axle, this was then filled with 2 part epoxy and sanded smooth. I used a slitting disc to knick the rim and hub and a scrawker to gouge the plastic wheel, the slitting disc tended to melt the plastic and depth control was....uncomfortable
The LNER tenders have deep flat external side frames so hide the CSB wire easily, Stanier and Fowler tenders have large oval cut outs so a CSB wire running across the bearing tops will show through the openings. In this case you may need to elevate the CSB wire clear of the opening, on the Fowler crab I simply added small hand rail knobs to push the CSB fulcrum clear of the openings.
Close up of hand rail knob, simply drill a small hole into the bearing and fix with super glue, you could drill deep enough so that the hand rail knob goes into the brass bearing, not sure how you would solder it though, might be a bit tricky getting in and out fast enough to not melt the plastic insulation, then you'd need to insulate the CSB fixed points...in my case small 0.5 mm tube and collect your pick up that way.
Overall the system seems to work well, though for some odd reason, the A1 doesn't roll as well as the Fowler tender, despite the bearings being reamed out to 4.8 mm and neither are lubricated, I think the Slaters blocks could be thinned as well, which I did on the Fowler tender as they can be seen underneath from low angles.
Hope that helps.
