[FT] What would you make this cost ?

I'm thinking about a vapour shroud variant to simulate a cloaking
device.

The vapour shroud is:

MASS: 5% of ship's MASS
Cost: 3xMASS
When active, owner cannot fire any weapons or launch or recover
fighters.
Attackers treat owning ship as doubly screened.

The cloaking device might be:

MASS: 5% of ship's MASS
Cost: Ship's MASS ?
When active, owner cannot fire any weapons or launch or recover
fighters, or
have other screens active.  For fighters or missiles to attack the
owner,
they must be within 2 units at the end of ship movement.  For a ship to
target the owner, the ship must successfully scan the ship (roll 5 or 6
on
D6 or get 2 "hits" from a 3D6 "attack" on a doubly screened target
(close to
equivalent)), then treats the target as singly-screened.