I have moved from a large case to using a couple of waterproof soft Ortleib bags instead.
Welcome Shakey! I'll hopefully see you next weekend...if only the weather is as good as we have enjoyed this weekend!
I bought Jay's "victorian leather suitcase": purpose designed for a Morgan rack and weighting 7kg EMPTY. Along with the present Mrs Aldermog I went to Jersey for a week, the case and two soft holdalls behind the seats were plenty. As has been suggested packing light is a man thing so I got one bag and about 20% of the case...!
As to the high level light, it is all but invisible. Not an issue here in Blighty but there are stories of the French Police getting grumpy about it. So a "clip on" LED strip under the straps would be the answer. The standard uit has a nice cable connector. The actual light unit is helf by 2 wood screws....takes 5 min to remove.