Don't do it, get the correct hardware. Shops have done the bolt thing for decades to get the car off the lift and out of the shop back to the customer because it's a business thing for them and they'll probably never see the car again. It really only works if you have an air or electric power tool that will spin fast to get the nut to snug up, if you're using a hand ratchet the bolt will spin and you can't get a wrench on the bolt head inside the body. The next guy who needs to take it apart almost always has to cut the bolt(s) to get the spring pockets out. When I see bolts I warn the customer that because someone used bolts in the past that they will almost certainly have to be cut. They will spin because there's nothing holding the bolt head and the nuts won't spin off easily due to rust or galling from over torquing and since it takes even longer to cut the bolts with nuts than grind the heads off the stock type bolts that are used with C nuts there will be additional labor cost depending on extra time required. When people use bolts they're almost always over tightened because "suspension needs to be tight!" and they're not aware and don't look to find the torque spec is only 25 Lb Ft for the stock bolts so they get cranked down "Good N tight".