Help! Replacement shelves for Cage that has Plastic shelving

Hi all,

I was hoping I could get some help. I have the larger equivalent of this cage: http://ift.tt/2F7hVym.

The width appears to be just shy of 18 inches and length appears to be just sh of 30 inches and the height is just shy of 30 inches. I want to replace the plastic shelves with metal or wood but want to keep them as same length and width. My Chin is just over 2 months and we just brought him home less than 2 weeks ago and he's adjusting so well, I'd hate to totally disrupt his environment. Currently he's showing no signs of chewing on those shelves but been told by a number of people it may be only a matter of time before he does, so would like to replace, but rather than redesign, wanted to see how I might get equivalent size and width without breaking the bank as ultimately when he's six months, going to get him a larger cage. I'm not much of a DIY gal, so was hoping folks might have some suggestions. Appreciate the tips. The shelves are about 17 X 10 and latch right onto the metal of the cage.