Opinions on my enclosure plan.

I know that the general rule for iggys cage is that it should be twice the length of them and thats including the tail. But I was looking around a bit online and saw that many people make the cage not so much long but more up high. Like having second and third stories. I was THINKING that maybe i could make an enclosure like this....

4 1/2 feet length wise

30 inches width wise

and 60 inchs high

my other option is this an already built enclosure that a friend of mine has the measurments are

6 feet lenght wise

1 1/2 feet width wise

and im not sure of the height but it could have two stories easy.
the problem is the width... well give some opinions. Nothing has started yet so these are only ideas. But the actual building of it is starting VERY soon.

Caging should be twice the length of the iguana tip to tail in width and three times the length of the iguana tip to tail in height, with a basking perch not more than 12 inches from the UVB source, as well as appropriate heat (ceramic heat emitters work well) and appropriate humidity. I don't personally own an iguana but my friend does iggy rescues and this is her advice regarding caging.

Okay well sounds like I need more planning and alot more room:P . I will rethink the measurements. Thanks for the reply:)