Do yourself a favor and go to Redneck's website, use the info on there, and call them.
I try to buy local when I can - I called a localish trailer parts place. I was waffling between a 2K and a 3.5K axle and needed help. It was clear the local place didn't want to talk to me and apparently didn't want my business. Maybe they thought I'd just order online after talking to them. That wasn't my plan. But they were no help.
I called Redneck. The nearest warehouse is about 3 hours away. The guy couldn't have been more helpful in wanting to understand what I wanted to do, and help me pick an axle, springs and mounts that would work for what I wanted. He spent more time on the phone with me than I could have hoped for. Shipping was reasonable.