Hi all, I'm trying to figure out the best way to frame a large photograph; 54" x 70". It is going to be mounted to dibond. I'm concerned the mounted photograph will bow due to the piece's significant size/weight. The frame is Beech with no glass. With a depth of 2 1/8', width of 1 3/4" and a rabbit of 1 3/4". I can alter any of the above slightly to ensure the security of the piece - whether it's the wood used, the design, measurements, etc. - Just need a valid reason to do so - the safety and security of the piece and the frame being a big one! Thanks in advance!