i've read this thread a few times now ,and considered all the replies ,i fish a few small rivers & streams with varying depths of swims and widths .
and would agree with Mr walker ,trotting is trotting .the only difference is in scale of tackle used .i do differ in my choice of length of rod i don't fish with a shorter than 10ft rod (even though a shorter rod may seem more appropiate) ,i prefer the extra length as it gives me more control once i've hooked the fish .i'll either trot through or stet-peg which a longer rod helps with .
if there's not much room at the waters edge too be waving a 10ft rod around i'll step back a foot or two ,too compensate .
its the other tackle i scale down line ,float ,reel etc
hooks depend on bait used (but i don't like tiny hooks ) a 16's most likley
line wise 1.7 - 3lbs b/s
reel 3½" - 4" centrepin or my 506 abu c/f or mitchell 410
float either the smallest chubba i can find (3bb) or one of my own special mini avons
thats a 3¾ inch centrepin (i have smaller ones) on a 11ft rod (more often a 10ft carbon rod or 10ft splitcane rod) ,with a 4" avon float that takes 1bb ,broken down as 2 no 4 as bulk ,and a dust shot as a tele-tail or 4 no 8's spaced out and fished from 3" to 4ft deep depending on water levels .
i can fish any small stream or river with this set up ,comfortably ,only flow rate would cause any change ,if a bit slow i'd opt for a short light chubba float because of its surface area ,they pick up the flow better and maybe a switch too a free'er running centrepin or c/f reel and maybe a longer rod too keep all the line of the surface (line from rod tip direct too float tip) over a longer trot through.
my private river stretch
3-3½m wide ,and between 6" to 3ft deep meandering river
here fishing under a willow ,had too sit a few feet back as i was using a 11ft splitcane rod
I was using a small chubba that day

and it took a longer rod too stop this monster from crashing into the streamer reed and snapping my light line (1.7b/s)
mind you .i also fish small rivers like these which have barbel too 7lbs in them .small rivers can be great fun wether they're coarse or game rivers or mixed like my local river erewash and one of my favorite grayling rivers the test (slow carrier at timsbury manor springs too mind) .