What do you use for bedding that they are landing on? Unless it's hard, like concrete, or has nails or sharp stones or something on it to cause injuries, I doubt the roost height makes too much difference. I've seen people have ladder roosts to the top of their barns. I'm just going off that since so many have it, it might be something causing their feet to get scratched or cut. We use horse pellets so that helps keep their feet cleaner as there isn't any poop they can walk in and it's dry as a bone.
As for will a tweezers work, it might help pull out the core, but don't you have to cut to get to the core first? Also, do you have PRID? It's a drawing salve. I've heard people try that first If the bumblefoot isn't too advanced. You could try soaking their feet in Epsom salt, then apply the PRID and wrap their feet with vet wrap, changing twice a day. If it's pretty bad though, you're going to have to do what you intended to do.