Rear shock install_problems
I'm assuming there's a little bit of an airspace in there at the center of the hourglass to ensure they're tight/preloaded when installed?
couple ideas-
1) hit them with a hairdryer on high to soften/expand the bushings before attempting to install?
2) use a 3/4" impact socket as a driver and tap the shock on?
3) find an 11/16" reamer or drill bit and ream them out?