Re: transformer clearances
I would assume that these are dry type transformers as you didn't say.
There should be installation instructions for the transformers available which should indicate minimum clearances required. Others wise consult the manufacturer of the transformers.
I would assume that clearances will not be the problem with your installation but cooling will be. I think that you will find it interesting to find out what the heating watts of the transformers is and the ventilation that would be required to maintain a reasonable ambient temperature.
Then, again, due to the minimum information that you have provided this is a educated guess as what your installation is.