So far I’ve concluded for daytime hiviz would be a good idea , I like yellow, but orange seems to pop well to the eye too.
Sam Browne belt in fluorescent yellow woven tissue (for breathability) with strands of silver reflective material for night-time visibility. I wear this nearly all the time. It used to work extremely well to attract attention, because it is similar to the equipment worn by French motorcycle police. But with the explosion in hi-viz jackets, it gets noticed less nowadays.
Most hi-viz stuff isn't very breathable and causes sweat build up when I wear it, so I avoid it when I can. But if doing long distances I generally wear bright coloured cycling clothing, for short errands I just wear ordinary stuff. In both cases I wear the Sam Browne belt over the clothing. For light rain I have a hi-viz Montane jacket, for heavy rain either a bright red cape with reflective patches or a Quito jacket that isn't particularly visible (with this I again use the Sam Browne belt).
Also a battery powered day running light
I generally only use the battery powered rear lamp during the day time in bad visibility (fog, rain).
For night , Dynamo light front and back , plus the daytime running light at night time
I don't have specific daytime lighting, I just leave the dynamo lighting on nearly all the time (I sometimes turn it off on bright sunny days when riding on roads with little traffic). The (bright) headlamp aids visibility and makes it more likely that cars will not pull out in front of me at junctions (car driver reflex - single bright white lamp equals fast motorcycle rather than slow bicycle).
So in summary, Dynamo lights front and back + daytime running lights , plus hiviz plus reflective
I add two strips of red reflective tape on my (big) rear mudflaps. A front reflector of some kind to comply with the regulations here in France (I don't consider it useful, the front lamp deals with visibility from that direction). And Sekuclip wheel reflectors that clip onto the spokes and are visible from quite a wide viewing angle at night, instead of the flat orange spoke reflectors that are IMO completely useless in most real-world situations. Pedal reflectors to comply with the regulations (not completely useless, but often obscured by touring luggage). My recent Ortleib panniers have reflective patches, but not my old home-made panniers or my old Carradice saddlebags.