Norton TLS front brake questions

I'm helping a friend try to improve the braking performance of his Commando twin leading shoe front brake and would be grateful for some advice. The drum has been skimmed true and the shoes machined to match, and a stiffening kit was fitted, all this being done some years ago. With very careful set-up, the Ferodo shoes look like they are wearing evenly. The brake plate is the original, not a new casting. The bushes for the cams are very good, with no play. I'm prepared to be realistic about this, but even though the TLS drum is less effective than a disc, I feel it should be better than it is. My questions:

— Does anyone have any data from old road tests that quote stopping distances for both TLS drum and disc brake models? We want to do some tests of the current set up to compare with the original road test figures.

— Les Emery claims that the new TLS brake plate castings are much stiffer and the new cables are stiffer too. Has anyone tried these new brake plates and how do they perform on the road?

— The bike is in England. Has anyone sent their TLS drum to a brake specialist in the UK with good results, and if so, who should we go to? Or is this worthwhile considering what has already been done?

I'd try a new cable first.

If you look at the chain of interaction it seems that the cable has the highest probability of stretch or distortion of the components.

I'm not sure if Barnett still makes the big cable for it, check with a dealer. They are pretty sensitive to lever adjustment angle.
That said unless you are racing it there is little payoff from going much furthur than you have. I've run these types for about 100,000 miles total and for every day service they are a good brake. They heat up too quick for track use and a series of mountain curves at high speed can make you wish you had gone to superbike discs.
I've done pretty much as you have on my current old drum and it is a pretty livable drum, the best of my drum brakes, and as good as my stock goldwing until it gets hot.