I am installing a Regency I2400 into existing prefab fireplace and the oversized surround that comes with I2400 is too large (stonework in the way) and the standard surround is too small (1" gap on both sides will be exposed). My plan was to go with the standard surround and have a piece of steel cut to cover the 1" gap on both sides. My question is do I have to have buy the Regency surround or can I just have the steel piece cut and push the insert against it? Would that alright or should I go with the standard surround? Thanks for any advice.