So a friend gave me a mint 1070s Bear Grizzly it is 58" and brown and green, 50@28. I draw 29.5 and was thinking 31" 2016 with 145 grain Bear Razorheads. Think I am in the ballpark?

Do you mean 2216 ? 2016 would be to weak of spine .

I think he meant 2016's. They are versatile shafts and should get you close, that or 2018's. I shoot 2016's with 125 tips and 100gr inserts, and get great flight out of a 50# kmag and I'm drawing it to 52-53# with my draw length.

I meant 2016

If they did turn out too weak, you can always build out the strike/side plate on the bow.

It's easier to make a weak arrow act stiff than it is to make a stiff arrow act weak. Now, if you're wanting a high FOC arrow, that is when you might want a slightly stiffer spine to begin with because more weight on the front will make the arrow weaker.

Historically a 2016 was always matched to a bow in the 55/60# range with a 125 gr. tip and at 28".  Depends on the bow and the shooter.

I have a 40# modern grizzly and I have 2016's that are a little too weak at my draw (28").  They are a little too long (31.5" w/ 100gr heads), but I think if I do 29.5" with a 125gr head, they should be just about right.  I currently have my strike plate built up a bit as well.  

I would go a little bit stiffer for a 50# with 30" arrows and 145gr heads.  

Also, are you sure .5" is enough to keep the broadhead off the shelf?  On my bow, I need a solid 1.25" beyond my draw length to get the head to clear the shelf.

I'd try a nice Cedar or Split hex wood shaft probably about a 55-60lb spine & cut to 30-1/2".