Echo this and add other sources like Zillow or Houzz...really great to get ideas, for free!

- Good source to find reputable and experienced small multifamily builders once we firm up a specific market?

If you’re just looking for money to fund deals and you’re thinking the source could be IRA money then it shouldn’t make too much a difference to you whether the investor uses their personal funds or IRA funds.

Using criteria like price-to-rent ratio, pop growth, employment trends, and wage growth, relying on multiple sources (PropStream, Zillow, Rentometer, FRED) to calculate averages. 

Meet ups could be a good source too since you’re in a big market. 

Show Financial Stability- Proof of Income: Military pay provides a stable and reliable income source that banks value.- Creditworthiness: German banks assess your financial standing, so keeping accounts in good standing is critical.4.

I consider the two best sources is from other trusted contractors and other RE investors.  

What are the best sources or methods you use to accurately set rental rates in your area?

Build - rent - refinance -repeat. in columbus ohio you are buying old houses that are 1900 or 1920 or 1940 and you are in a sellers market. on the other hand you can source land which is a buyers market and build single family homes or duplex or triplexes that will return by renting and pulling cash out on a DSCR loan and doing it again. there aren't a lot of strategies that do this. flipping is different. so many risks. but when someone has a well oiled machine it's all good and less risk.

The data @Devin Conley posted is pretty solid from my experience (I do not know Devin nor how he sourced the data, just going by my own investing experience).