Hi Squirrels,
In Hungary we have not good trout rivers then the Hungarian fly fishermen fishing for coarse fish (and pike,zander,etc.).I would write down some very nice flies for chub,roach.
At the first time to the chub.My friends use the simple black polifoam beetle(hook size 12-8) but I prefer the "naturally" flies like Coachman,both dry and wet,March Brown,Soldier Palmer and at the end of the summer is very good a bigger hopper.If you want to catch bigger or the biggest chub

,you have to use smaller streamers.The chub likes the yellow/black streamers and the Muddlers.My first choice:leader fly:a Spuddler and the dropper is a wet Coachman or March Brown.The March Brown with fluo orange floss body better than original,I think.When I use dry fly,the first is a 10 sized Coachman(not Royal!).
Roach.I have already caught good roach with fly and my favourite nymph is Pheasant Tail with fluorescent orange thorax( the hook size 16-12).I have read in a German fly fishing book the roach love the fluorescent orange.It's right.
I hope,it will be a little help to you.
Cheers,
Levente