Has anyone compared the HK brand light to a Insight M2 or Surefire M2 for a full size USP. The reason i ask is i have a Safariland tactical drop leg holster for a HK USP 9mm w/HK light. The HK light is very expensive compared to the Surefire or Insight M2 lights. If they are all the same size i would rather buy a cheaper light as this is just a practice rig. I just need to ensure they are all the same size before i make a expensive mistake. Thanks for any help you can provide.