I've voted for plain boards good, lenses = tat, I'd think the flag (Italian) number boards would look good on a red bike but no so great on a yellow bike to be honest, but the whol lense cover thing is terrible
I agree about lense covers for coloured lights but I was just trying to achieve the complete numberboard look, but if everyone thinks it looks tat then I'd rather save my pennies for something more worthy.
One thing I would say .... if you are not 100% sure why not get them put on in vinyl decals first. Give them a try, different styles etc etc. If not happy then take them off and t-cut/polish the bike.
All my Xerox livery on the carbon749 is done in decals ... not a drop of paint at all. Easier than paint to swap.