I'm planning a 16/2/2 bard/fighter/rogue with the Finding dragonmark line. Now the dragonmark will give me the Knock spell, but I'm not really familiar with how well Knock works as opposed to Open Locks. Will an extra 10 or so ranks in OL above the initial 4 let me open things I wouldn't be able to open with Knock? Or can I save my skill points and use them on other utility skills I would otherwise be neglecting (jump/balance/etc.)?