I have seen bumpers plated by Superior Bumper (I think that's the name) in Houston and was not impressed at all. I think they just do the chrome/nickel instead of the full blown copper/nickel/chrome triple plate process. In any event, I was not impressed with how the bumpers appeared regardless of the shine, etc...too wavy, etc. Apparently, DalChrome (Dallas Chrome) doesn't triple plate either and it shows in their work.
You could consider or call Speed and Sport. Cost is much higher....recently ran approx $650 or so for a 70 Olds front bumper. Triple plated and they did a nice job. The rear bumper was a similar cost but not as impressive of a job....the 70-72 Olds rear bumpers, however, are shaped such that any imperfection will be very apparent across the top half or so of the bumper (it's a long FLAT area).
Were they better than what I have seen from Tri-City Plating out of Tennessee?? (at a substantially lower cost also) ...in my opinion, NO. At most, the Speed and Spot work may have been equivalent.
You should consider boxing and shipping to Tri-City. The key on the front bumper is to run something STIFF (wood or a steel bar) across the backside of the bumper so it won't flex if dropped on one end or someone jumps on the middle of it during shipping (ask me how I know this

). Also..CLEAR INSTRUCTIONS TO THEM TO DO THE SAME WHEN THEY SHIP IT BACK.
Hopefully, those are some ideas to help get you started.