For my power wagon and several of my customers we just bought the $99 Amazon two and a half inch kit that has 180° 90° and 45° bends and some straight pieces with flared ends...
I used an extra bunch of jack stands to kind of hold it up in place as a puzzled it together. Put the flared and you can just slip one piece into the next. If I needed to do any kind of quick 45s around anything I took a piece of two and a half inch tall paper by a foot long and cut it in the drawer and made it out of paper and then made it out of pipe on my bench..
I tried to get three tax everywhere to keep everything in place and then pulled it all down took it outside and welded it all up with my $89 harbor freight 8-year-old welder. The same weather I used I never buddy else's...