My suggestion to you is:
1. Interview Realtors.
2. Have them analyze your situation and give you their proposals Let them know in clear terms what you expect: When you need to move, how much you need to net, etc.
3. Compare the proposals
4. Evaluate their negotiating ability: Many "top agents" are actually "discount brokers". By that, I mean that some use commission rate as their selling point.
The big question I would ask myself is "if this is how they negotiate their commission, then how are they going to negotiate the best price and terms for me?"
I would also advise you to focus on how they propose to market your home. The listing agent's job is to analyze your home's features and promote those features that buyers will think have the most value. A great example is a property that has extra storage space. It may be to top of the garage, it may not be permitted living space, but how big is it? How would they promote that space to give it value?
In addition to features, how will they get the word out. To find out, ask each Realtor for a listing that they currently have on the market. Type the address in Google, and see what comes up. They might say "we market on 25 sites", but what does your google search show?