That's the key -- the lift arms have to be able to move laterally to unhook or hook up an implement. There should be some relatively simple way to take the tension off the limiter chains. My DX has a telescoping tube with cross pin arrangement, Kubota's have turnbuckles. I remember my old 8N had chains, but I could move the arms toward the tires to detach them from the implement.
Are your implement pins facing outward? Some guys mount them facing in. If I remember right, the chains on the 8N limit movement toward the center line so the two sides work together to keep the implement in line. If your pins face in, then the chains would keep you from taking things off.
On the other hand, if your chains are anchored by the center of the axle, they would work to keep the lift arms from moving toward the tire on each side and you would want your pins facing in to allow you to move the arms toward the center to detach the implement.
Either way, there should be a little slack in the chains when the implement is sitting level behind the tractor.