Healing Macro Help

Trying to utilize the Enhanced Renew talent with feral druids, but I can't seem to get a decent macro working in order to have semi-control over the Rejuv.

#showtooltip
/target Gribblets
/use [@mouseover,help] [] Rejuvenation
/targetlasttarget

Is what I am using now, but I know it isn't the best way.

I have been trying to play with:

#showtooltip
/use [@mouseover,help][@Gribblets] [] Rejuvenation

But it just doesn't seem to be firing.

As for my setup in ISBoxer, I have two keys setup for casting it.

Hotkey 1: Press 1

Actions:
Do Main Single Target DPS Macro to All Screens
Do Rolling Rejuvenation to All Screens

Under my Main Single Target DPS:
No hotkey

Actions:
Send Key 1 to all Windows (in game is the main DPS macro)
Send Key 3 to All Windows (Healing Touch Macro via Mouseover) works fine
Do Rolling Rejuv to All Windows

Rolling Rejuv
No Hotkey
Advanced (Reset to Step 1) After First Press in 12 Seconds
Actions
Send 4 to all windows

But it seems to be spamming the rejuv more than every 12 seconds.

If I need to post my config or clarify please let me know, I am typing this up as I am running out the door. :)