Is the riser where you want it? If not, I suggest that you get rid of that 180-degree bend! Well, suggest you get rid of that anyways.
There are numerous ways to build an industry standard shower...it's not hard, but is very detail oriented. If you haven't looked at a surface membrane verses a 'conventional', liner shower pan, you should consider it. Been around now for about 30-years, and IMHO, much better than a conventional shower. At least a couple of manufacturers, but Schluter and Laticrete both have good ones...Schluter's has been around much longer and has a larger amount of accessories to handle various situations, but both are quite good.
Suggest you check out
www.johnbridge.com for help in constructing your shower. Ask your plumbing questions here, though.