I personally can't accept anything lower than 65-35 without feeling like I'm misleading the Olimar players that come here for guidance. Unless some more Olis come in here and agree to 60-40, that is. It's really a miserable matchup if the Luigi does it correctly, and I advise every Olimar player to get a secondary for it.
hippiedude92, all you have to do is short hop fair->nair onto the Olimar player's shield and jab afterwards. If they shield, you jab cancel to grab. If they don't, you combo them till they die. If they run backwards and you see it, then let him! He'll get cornered eventually. He can't pivotgrab forever. Just avoid the pivotgrabs and spam that one approach and you'll win every time. The only thing he has to combat against it is standing upb, but if he misses, he'll lag enough for you to fsmash or firepunch him if he's at a high percent or just throw him up into the air at lower percents. Don't edgeuard with bair, but rather fairs and dairs, and then if he whistles, quickly use a nair to punish it. I promise you you'll do very well against Oli if you do those things.