I'm using Hobbs HeirloomŪ Premium 80/20 Cotton Blend and the package says 3.5" but the website says 4". It only mentions quilting, not tying. I use Hobbs 80/20 because I can get 2 charity lap quilts out of one queen size batting. I buy the batting with a 50% off coupon at Michaels, making the cost about 4.50 per quilt.
I made these quilts about 2 years ago when I was a very new quilter and I probably didn't even read instructions before I suggested 5" for the distance between ties. Live and learn! I got sidetracked by moving, but now these need to get out the door. I'll post photos of all 8 quilts after I launder them.
"HeirloomŪ premium 80/20 cotton blend is one of our most popular battings because it offers more loft and less weight than traditional cotton battings. Our 80/20 is made with 80% natural cotton & 20% fine polyester. It is needle punched and spray bonded to provide exceptional strength and durability. Shrinkage of 3-5% and may be quilted up to 4” apart."