As a general piece of advice for them all, avoid the very back row as that will provide the roughest rides which can be particularly bad on Grand National and Big Dipper. For the smoothest rides then sit in the middle of the carriages as they are not above the wheels of the train, but this only really applies to the two mentioned above. The wild mouse is a bit rough at the beginning of the ride which is unavoidable but the rest of the ride is fine. However, I would not describe the rest of the ride as smooth, as it is just completely insane which makes it a love or hate coaster. Like lofty said, you don't need to worry about roughness on the nick streak and blue flyer, but towards the front is better on nick streak, IMO it is a very underrated woodie