This question is likely better answered in the tax section or by a CPA. That being said, you're letting the tax tail wag the dog. If you're really concerned, then estimate your self employment taxes and weigh your net income from self employment against your net income from working part time. Take the higher of the two.
Do not assume that there are mysterious deductions available to you that attorneys will find. These mysterious deductions and write offs are largely media exaggerations. I rarely encourage people to make financial decisions based principally off of the tax effects. Taxes are something to deal with in relation to other larger concerns, such as the potential for you to turn your part time job into a full time job or develop your self employment business into something more lucrative.