I made both 90 and 45deg joins out of scrap 38mm pipe. I used the templates generated by the calculator above and cut them out with an angle grinder with a 1mm cutting disc, cleaned up with a sanding flap disc. They fit nice first go but I am still getting the hang of the new welder. By the time I found the sweet spot I'd finished the joins.
I am strongly considering buying a pipe notcher for the consistency and repeatability required, but it is good to know I can get good results free hand.
I'll go an buy a heap of scrap pipe this weekend so I can get some decent practice.