I've kept my three bareshafts for that purpose as well. Didn't realise how bad my form was until i started bareshafting. Not sure how much was tuning to start with and how much was me as i only just started shooting again after 6 months injury, but as i've been using the bareshafts and tuning as well i've been able to identify form issues much easier with the bareshafts so i'm definitely keeping them in my quiver.