neutering kittens that self nurse ( smurgle)

My kittens are big enough to get spayed and neutered now but Mimi self nurses on the inside of her thighs and sometimes allows her siblings to also do it to her. The other two kittens really only do it to her, when they hear her going at it. She will get up and walk away if she doesn't want them to. I have once or twice caught them trying to do it to the little boy but I stop them because I don't want his penis damaged. 

How effective are the e-collars for kittens? Is there a better method to get them to leave the incision alone? I'm mostly worried about Mimi pulling the stitches out. She self nurses multiple times a day. The other kittens rarely self nurse but will try and join her when she is, once or twice a day. The are pretty easily redirected to other activities, unlike Mimi who is determined. 

I've debated delaying her spay a little longer hoping she will reduce her activities some over time. They are about 3 months old now. 

You can put a tube sock or baby onesie on her so she can't get to the stitches. Those work better than e-collars, IMO.

I ended up using bitter apple in the dab on bottle ( not the spray) after confirming with the vet that it was fine to use nearby but not on the incision. It worked great. The neuter actually was left open, no stitches or glue and the spays were glued on the skin with stiches below. They all did great. Obviously I'm very late getting back to this thread. I got through the recovery and then we ended up moving so I didn't get back here. 

My kittens did the samme. They stopped at 4 months and we had no problem. Are kittens never reached there heat.