Used this guide for a mid-2010 chassis, which seems the same. I'd recommend moving steps 23-25 to happen between steps 3 and 4. Basically, take the battery out first, immediately after removing the bottom cover. Also, replace it as a last step in reassembly prior to placing the bottom cover back on. What I found was that placing the logic board back into the machine (reversing step 22) was difficult with the fairly stiff battery connector cable. If you have better mojo than I do with a spudger, good on ya mate.