PE pipe

I want to get a jump on my shop heating issue before winter officially sets in up here in the northern climes. I have a long run for NG to my shop, and have a question regarding using PE pipe.

First, how many of you have used this underground? I have a 25’ run between house and shop. Second, because I am using black pipe, how far below grade do I have to be in joining the two? Finally, how flexible is PE? Once I come into the shop, I need to make a 90 degree turn up. Would I be better running black pipe out into the ground rather than trying to make a radical bend?

-- No matter how many times I measure, I always forget the dimensions before I cut.