Sorry, I can't remember really ><
Considering I was using no MDT gear though and still managed to survive I'd say "not enough!" XD
Just make sure your shadows are back up as soon as the spell is over and you should be fine.
If it can be of any help, this is the eva/sb build I was using.
As you can see, it's far from perfect so hopefully it will encourage you.
Haste gear for Shadow recast and then back to that ^