I am fitting braided hoses and so will be changing the fluid too. I already have Motul RBF660 Dot 4 spec fluid but can't remember how much I need to buy.
If you're doing the lines yourself, how much fluid you need also depends on how much you let pee out whilst swopping the lines over.
also note it's incredibly easy to let air into clutch feed pipe on master reservoir as it's located half way down the reservoir side but hidden behind engine air filter container (silly design) meaning before the reservoir is empty there's already air in clutch line, that said should really bleed clutch at same time, quite easy, keep same fluid in both domains.
Good brake maintenance keeps a firm pedal and trimming out any slack on the rear TRW self-adjusters which can give a constant pedal travel issue.