BitBucket Version Management Setup - open to bidding

INTRO: This project is about a straight forward BITBUCKET SET UP to allow for version management. This project does NOT include any work on the code itself. JOB: It has not yet been decided if to use git or mercurial. I want to discuss that with you. I do have some php code ("base") which had subsequently been customised ("custom"). For the "base" is now a new release available ("new"). I want to use BitBucket to compare the "base" and the "custom" code to identify the code differences between those which had been introduced during customisation. Then I also want to compare the "base" and the "new" code of the non-customised base code to see which code has changed for the new release of the base software. I am looking for someone who can help me and setup my BitBucket account so that the above version comparisons are possible and further changes and merges can be managed. On my system I am planning to use SourceTree (on Mac) to sync with BitBucket. A basic, simple document, outlining the essential steps to use BitBucket for the above tasks will be written (I can write it up, but I need your input and for you to review the document and check for correctness).