@Brendon W. It is not specific to Pittsburgh, This is the same method to use anywhere.
I begin by going 1/2 mile radius and sales within the last six months.
Make sure the style of house is the same, ranch to ranch or bungalow to bungalow etc..
I look at age of home and make sure they’re within 20 years of each other.
Look for basement versus slab. Make sure your comparables have the same foundation if possible.
Bedrooms and bathrooms being close to equal amount is certainly important, but I believe your question is how to adjust the comparable if they are not. My answer would be that you are not needing to be this spot on for value.
Remember that an appraisal is just an OPINION of value.
Look at everything, market time is a big indicator on how much value you can lose from going from three bedrooms down the two bedrooms or from two Bathrooms down to one bathroom. Then that is the point you take a guess on how much of a price reduction would be necessary to get the inferior property to move as quickly as one with more features.
Typing all of this is much more complicated than just explaining it, I need to find a way to just post a video LOL
I’m actually out in Pennsylvania quite a bit because my wife’s family is from there, it’s a great market!
Best of luck!