The Cherokee(and probably others) had 100# war bows but that is just what they were, war bows. Their day to day bows for hunting and regular defense were probably from 40# to 60#.(just a guess)
What was Outzi up to when he was attacked.? Was he on regular travel, going from point A to point B, was he on a hunting trip or was he trolling for marauders? In any of these casers I would think he'd be carrying his everyday bow, one he was used to shooting on a regular basis. For hunting or self defense he would have a bow he normally use. Why was he carrying partially completed arrows and bow blank? Had he lost or broke his regular stuff? I believe he was 6 hours or less from home when he died, at least by his stomach content. Would that have been enough time for him to get where he was and collect and work of the bow(to be) and arrows? Did he bring these things with him from home to work on along his journey? I guess we will never really know.