honestly, till it feels tight lol.
ive always used to try and do the smart thing lately and torque things to where they should be. but after snapping 3 bolts by doing so, ive learnt to just do it till its tight, and aint going anywhere. with shock mounts, id go till the bushing slightly swells. not to far though or it will run the risk of being to tight and splitting and becoming useless.
however, if you wish to torque them, I cannot help you there.