Stahala Bed Risers (Set of 8) Lifts Height 1",2",3" or 4",Natural Wood Bed Desk Chair Couch Risers,Heavy Duty Bed Risers,Furniture Risers for Sofas,Table Legs Extenders with Non-Slip Rubber Pad

Q: Do they work for large Sectional couches?

2 things here. One, the legs othe sectional must fit in the risers. Once the risers are installed you basically not move the furniture. So unless you can easily install the risers, it's a lot of work. However, they do allow for more clearance under the furniture..

Q: Don't understand the quantity...are there 8 sets of 4 so you can go up to 4" for 8 legs or just the 8 pieces

There are 8 pieces for eight legs

Q: What is the weight limit for this?

I have them under my sofa and my love seat, so far they have been good withstanding the weight. I always moving my furniture around and they have been great with sliding my furniture around. I have hard woods so I really dont have to remove them.