The 18x18 is alittle small for a male. Also the odd size makes so you cant install normal 22" T5 or 24" T8 bulbs so your light choices are alittle limited.
If I was in your shoes i would make your own cage. You can customize the enclosure to the size you want. 24x24x48 is the recommended size. My enclosure both for my male veiled and female is 24"x30"x48" enclosure itself, stand makes it 6ft. I've heard many pros and cons about the aluminum enclosure and for the price you can make your own. That's. Just me