Bumps in planes are a function of 'wing loading'--essentially how large the wing is relative to the weight of the plane. Inertia plays a role as well--a bigger plane just takes more "oomph" to disrupt stability but a bigger plane is also exposed to more "oomph" so turbulence is relative. The combined factors mean pilots of different sized planes often feel the same degree turbulence or chop: if one reports 'moderate' others start inquiring about alternate rides despite plane size; if somebody reports severe, everybody starts taking other routes/altitudes, again despite size. Morning flights only help for turbulence in departure/arrival due to heating; strong jet streams , convective activity, and mountain wave are kinda time independent.

For the smoothest flights, since timing flights is often not an option and aircraft size is generally neglibigle, I'd offer: sit as close to over the wing as you can (plane's pivot point--bumps are worst far forward and far aft); drink something lemon-lime or ginger ale; avoid greasy food; sleep thru it; avoid Denver or any other city on a front range (downwind) of a mountain; key off the Flight Attendants, if they don't seem too worried or are up and about the bumps are not uncommon or perceived to be too bad; and don't watch the wing tips--you may not like how much they are flexing.