How would you stake if you knew you had an edge but didn't know what it was?

[Sand87]

My main question is a little hypothetical. Most of us can look at a market and realise when the odds are way out of line without having to know what fair odds would be. For example, in the unlikely event you open Man Utd v Chelsea Correct Score market before kick off and see Man Utd 1-0 @ 500 you don't need to know the correct odds to know this is a value back. And obviously you would stake as much as you can because you know the market will eventually correct itself. But lets say the difference isn't so large that you are confident the market will correct i.e there is risk attached to the bet and so you need to protect your bank. How would you stake if you didn't know the true odds? Betting 0.5% of your bank on odds between, say, 1.50 and 2.00 is a fair deal. But would you then stake the same % on odds of 110? Of course not because you must expect many more losses to your wins and you may well go bust despite getting value. Once youv digested that :D , I'd like to ask something else: For a couple of years I used a set % of my bank for bets. I didn't vary the % depending on the odds because the odds were always within a very tight range but I recently decided that I want to move to a fractional kelly staking plan. I'm thinking 1/4 kelly to start with. I can do this because I can calculate with a fair deal of accuracy what the value on each bet is. But without using a bot I am having a headache trying to figure out how to implement this when odds (and therefore kelly stake) can change so often and I'm betting in many markets. How can I manually calculate the kelly stake each time something changes?