Thanks very much for all the input. And the level based puns! I totally get what's been said about the accuracy of smaller levels etc but I'd still like to give it a go. There is a flat spot on the stock at the back of the action so would use this as a level point. As for my door frames my house is 120 odd years old so I'm thinking they might not be true! Will have a look at those recommendations and see how I get on. Cheers all