if it is to be in a bag or toted all day on you belt hiking or hunting, maybe strapped on the side of your hunting day pack your not going out to chop logs or 3 cords of fire wood.. I think it would need to be light and fast. some folks may argue but the mini sized axes are awful handy and they are about a pound and a half and under a foot long, though you could lengthen the handle up to 16 inches. Get some head speed if you wanted. But must consider the jobs for this tool splitting pelvis or rib cage on game, chopping or splitting kindling wood, breaking up downed branches for fire wood or shelter work, or more than likely carried around the yard cutting sprouts and suckers of all my maple trees. So I think and we all think different stuff, I would want a nice little axe under a pound and three quarters and an axe should have a tad heavier head than a hawk and to keep this lighter, the handle could be high quality wood made finer and short so it can be packed in your bag but easily brought out.
Kinda rambled on this, but, a foot long at the most, 2 1/2 inch cutting edge, at a pound to pound and a half. if it has a hawk length handle then it would be a hawk and not an axe, this is where most of the difference is.
Pat