We are fine art dealers and sell many oversize pieces. There are certain items that we always have in stock. .125 48 X 96 inch acrylic. For larger pieces .250 acrylic decreases bowing. If a mat is required larger than 40 X 60 than we recommend liners (end wrapped)their use creates a more stable frame. We make every effort to maintain C/P. We always have reinforcing products for stabilizing long spans in stock. In addition, we counsel the client if they choose a frame that we do not feel is substantial. Two different people on our staff measure twice, measuring mistakes can be costly. A team of two works together and remeasures every step. We check and recheck. We order chops on the frame and liner. We also have a Dodge Grand Caravan which is I believe 10-12 inches long than a regular Caravan. We haven't had to rent a delivery vehicle since we acquired it. It also transports 10 ft sticks very well if we run them between the bucket seats. Lastly we keep angled steel brackets in stock that we use to reinforce the corners. We V Nail more and glue more and let the glue set up longer. Then we reinfore the corners with the steel brackets. Our largest piece under acrylic was 84 X 48 inches and it took two people 8 hours to assemble.
It gets easier the more you do.
AL