I know there're companies out there who'll do this, but end up charging hundreds, if not thousands of dollars, for what I see as simple analysis on a deal-by-deal basis.

Just don't go hundreds of thousands into debt to get one.

the list comes up with hundreds of match's and I don't have the patients to scroll through them all.. 

Honestly I don’t care if someone refuses to pay their credit card bills...those people have to have somewhere to live too and a credit score can go up and down by a hundred points in a few months.

You may not find a situation where you will cash flow very much (you may even still have to pay a couple hundred bucks/month) but at least you are now owning a property, not throwing a large chunk of your money away in rent (assuming you rent now), your tenants are paying down your mortgage, you are gaining equity each month and gaining tax benefits. 

I've already listened to hundreds of podcasts on flipping and plan to do more buy and hold anyway, but just wanted some input on how people recommend getting educated to feel comfortable estimating costs and successfully completing a decent size rehab job.

So for a few hundred dollars more, got it done.

I'm not a plumber but I've seen hundreds of homes and don't recall ever seeing one that shared a water supply line between the toilet and the sink.

Makes a big difference.Save yourself loads of future agony and call a local RE appraiser and for a few hundred dollars they can appraise it “as is” and after renovation” using only 2-4 multifamily comps (sale and rental) Then you’ll know your numbers.  

You can have a dumpster delivered / picked up right from the site for a few hundred bucks.