dave, get yourself the staking machine, its only 29.99 for a years use, its the best thing ive ever done, you have a choice of about a dozen or so staking plans, ive increased my profits massively since using it, i particularly like the saver plan but you can assess the perfomance against all the other plans at a click of a button.
you can download the demo for free and input up to 10 bets at a time so you can see what it can do,
when you see how many of the plans beat level staking and also are not to aggressive on your bank it pays for itself ten fold.