As said it the preperation that is key,i'm sure white would still take a good shine if its polished properly first.
Tub isn't that small and a whole car hardly uses any so it does last.
I did my FRS before fast ford at crail end of last year,
Full de-grime with meguires quick clay kit,
then a polish with meguires cleaner wax,
two coats with meguires tech wax,
a coat of auto glym extra gloss protection,
meguires quick detailer
then 7 coats of auto glym HD wax lol (yes seven!)
Took me a whole week of evenings to do but fcuk me it was worth it lol