tbh the money you'll spend on a decent bonnet bra you might as well get a professional to respray the bonnet for you... and you won't be called gay as a result!

claying won't take hours... here's the simple process
two bucket wash using a decent car shampoo & mitt - not sponge! making sure you get into the nooks & crannies, under window seals etc
dry, preferably using a waffle weave
clay using a megs or sonus clay bar and a detailing spray for lubrication
wash again
dry again
polish/wax - you have to reseal the paintwork after claying or it will be unprotected
the polish and wax part is another process entirely.. depends on budgets, finishes required etc etc
the clay part will add about half an hour to your normal cleaning... depends on how detailed you want to get though and how much you need to clean off... take your time with it
you never know you might catch the detailing bug and then you'll get OCD and be fcuked like me and some of the others!