2D6 with modifiers.  Ability modifiers will seldom exceed +3 or -2.  Skills:  -4 for untrained, 0 for base familiarity.  +3 is very good indeed.  Normal success target is 8+, higher depending on difficulty level and circumstances.  This is a System-Lite game, I've conluded that some rules are often necessary to encourage mature behavior by the players.  Anybody who wants a more detailed explanation for what is going on as in "How the hell did they sneak up and get the drop on me?"  will get one.  Don't worry about me cheating as a GM.  As a Gm I have often cheated on die rolls - in favor of the players.