Re: Hi Bay hanging
I had a unique opportunity at the last place I worked, there was a metal fab shop next door.  I used angle iron a lot to hang high fixtures and large j-boxes.  He would cut them to length for me, punch holes where I wanted them, and bring them to me for about half what it would cost me for a unistrut setup.  I also had him fabricate panel and transformer racks.  
 
 Another tip, buy your strut in 20-24' lengths, without slots.  You can save a good bit of money that way, and often times have less waste.