There are so many things that factor into your lift height with leaf springs it's hard to give a definitive answer. You have your spring hangers, the shackle length, shackle angle, the spring length, thickness, free arch, and spring rate that all factor into how much lift you will get out of leaf springs. So it really depends on how you set up your suspension if the 4" YJ springs will work for you. And a matter of trial and error if it'll be enough to clear the tires you want.
I used Rancho 44150 springs, which are 2.5" rear YJ springs in the front of mine. But they ended up being too soft, almost flat at ride height. My dad runs a spring shop, so I ended up building a custom pack off of the 44150 springs. IIRC I pulled the 2nd leaf out of the original pack and added two in it's place. The results were an increased spring rate from 235lbs to 250lbs, increased pack thickness by 3/8", and retained the factory spec free arch and length.
Once the springs settled, with my setup, I sit 7" over the stock BII ride height.
ON 39" TSL's
Hope this helps.