I have tried Kiwi with some cement perches over the years (more for perch variety and texture than nail trimming), and they do absolutely nothing for his nails. He uses them occasionally to get where he's going, but he doesn't sit on them or anything. I have heard numerous times they irritate their feet, so that's probably why he doesn't get on it much. Seriously, you can put the best cement perch out there in your birds cage, and if they don't step on them very frequently, they're basically useless. Think about how many times you have to "swish" the file back and forth to do anything when your filing your nails with a nail file. Parrots have far thicker nails than us, and they aren't going to instinctively give themselves manicures. Imagine how many times a day your bird would have to step on that perch in exactly the right way for it to file a talon down?
While I understand you need an avian vet for treating sick or injured parrots properly, any vet really will be able to clip talons, and will have styptic (stops bleeding) on hand if they clip too short. Some pet stores even do it. Just one more thing, if you don't have a local avian vet, what if your bird gets sick or injured? You really need to look into that. Many rural areas too small for a dedicated avian vet have exotic animal vets who can be quite experienced with birds, they just also treat reptiles and other animals that aren't dogs and cats too. Maybe look into if there is a local exotic vet you can take you bird to?