When you send a quilt to a long arm quilter, how much larger should the backing and batting be than the size of the quilt? Does it matter what kind of batting you have? I am asking for a non quilting friend who bought some fusible batting (not knowing what kind to buy). Thanks for your help.

Each LA quilter has different specifications so I would say check with that person.
Hope this helps!

I like long arm quilters that offer extensive services, which to me is: long arm quilting, include the batting & backing, binding & shipping all for one price.
I've read so many ads for Long arm quilting that offer specifics and particular needs.
The last Long arm quilter I hired did a beautiful job on my full sized quilt and she provided the batting plus backing. The only thing I had to do was the binding when I received it.
All this for the price of $90.00, but I sent her $100.00 instead.
JMHO.

The answer depends on the longarmer. It may vary according to what kind of longarm she has and how she prefers to load the quilt on the longarm.

It's generally 8" more than the quilt top's length and width measurements.

Batting does matter. I don't know how thrilled a LAQ-er will be with the fusible batting. Since it's still in the package - not bought off the bolt - maybe your friend can exchange it for regular non-fusible binding.

oooh, I didn't notice the part about fusible batting. I don't quilt for others, but I wouldn't want to use it on my longarm.

Like others said it just depends on the person. My grandmother provides the batting for every customer. She will for an extra cost provide backing and binding. She generally likes for there to be at least 5 inches extra on each side.

I like 4" on each side. I supply 80/20 batting, but will allow the customer to use their own batting as well. I do not have any experience with the fusible batting, but I'm not sure that it would work well on a longarm.