Not all 49s are created equally, nor are all our interests or applications. Realistically, if your primary interest is building a daily rider/commuter just about any decent 49cc four stroke is more then capable of carrying only 150kg/330lb as a motorized bicycle. For an example my ebike is a mere 1.3hp,
half that of the typical 49cc four stroke and yet it performs perfectly well with my 90kg/200lb carcass on it, even hauling a trailer & cargo.
If you live in a particularly hilly area you may wish to consider gearing if possible but even just some light pedal assist would suffice with just about any 49cc four stroke - as another example here's my 49cc four stroke laden down with camping gear and random junk for a total of an approximate 226kg/500lb, yet I had no problems whatsoever keeping up with the 49cc two stroke mopeds and scooters I was riding with at the time...
...granted it's a hybrid, but the electric assist doesn't help at all past 20mph and in fact hinders it (drag) - I could have had equal preformance pedaling take-offs.