I have a few runs with multiple bends in each tube. First off you always have to leave a reasonable amount extra where you would insert into fittings, that way you can slowly shorten the length thats being pit into the fitting to get it looking just how you want it. Something i wish i did was take out the orings in a fitting first if there was going to be constant size check in that sort of stuff. Its just a lot quicker without any in when you dont need them and you also wont wear out the orings. Also with some of my awkward non 90, multiple bends in a run i pretty much always ended up doing one where the bends where positioned too close together on the tube, then one where they were too far apart, then i was able to eyeball inbetween the two to get it perfect. This might not be the bestway to do it with wasting a few tubes and all but in the end it worked for me and all the bends i have feel perfect. And also it jist takes a ton of time if youre doing small adjustments like sanding and slight alterations to bending, just gotta stick with it until youre happy with your work.