Six shots may be enough. I wouldn't worry about bulky, depending on barrel length chosen.
Some people may be proficient enough for this to be an acceptable choice. I doubt the average person has the needed proficiency.
Five shots actually, if one is to carry a real Colt SAA or a replica like the Standard Mfg or a 4-click Cimarron. The old Cowboy Load; load one, skip one, load four, with the firing pin resting on an empty chamber for a total of five.