i ran my 88" (200tdi 3.54 diffs and overdrive, 90mph capable) until a year or so ago on standard 10" drums no servo and that stopped just fine, due to the lack of servo it just required that i leant on the brake pedal a little harder when needed
eventually due to the m/c leaking and me having a dual line servo setup sat on the shelf i fitted it, it just made the brakes lighter to operate
i've since fitted an 11" rear axle brake assembly to my front axle just because i fancied the experiment, it still stops like before but i think the shoes last a fair bit longer and with less frequent need for adjustment
the only problem i think i suffer now is they take a bit longer to dry out after wading and they hold more of the muddy stuff after the pay and play sessions