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?