only one of three letters is from academic faculty... bad?

[StenoLubr]

So the main question is that how is having only one letter by the Professor from the class I have taken.

 

I have a professor that I took a class in senior year and helped him editing his book as a research assistant. 

 

I know that you are advised to have at least one letter from someone that taught you in class. But would having just one bad relative to having two?

 

I am planning to get two other ones from faculties at the lab I worked at (but never taught me).

 

 

Another question is choosing my last writer

 

I have worked with two person at a lab in top institution (one was a visiting post doc and the other was a post doc at the lab)

 

I have worked close with both and the visiting post doc is now an assistant professor back at his country and the post doc is still a post doc i believe. 

 

I feel like the current post doc would write me a better with recommendation, but I heard from someone that I need to get all the letters from someone with title 'professor'. any thoughts on this?

[Monochrome Spring]

I got two letters from faculty and one letter from a post-doc who knew my research very well. It didn't seem to hurt me, but it can be field dependent. In my field, we pick the advisor we want to work with and chat with them before we apply. So I already had a rapport with the program. The letters served more to confirm their beliefs about me and double check that I was right for their lab group.