Have you ever tried it sub-q? There's plenty of rotation options if it works for you. With "me" Syntheselen cause red welts that take a while to go away whenever I use it sub-q.
IM rotation for daily shots could be delts (2), glutes (2) and quads (2) for 6 sites, nearly a different one ED of week. If you don't want to do quads maybe you can throw in some sub-q?
xcel