Jink & Cover saves

[manrogue]

I don't think it does as it is a version of cover save and not a modifier. Stealth and shrouded stack as modify the cover save whereas Jink and a ruin (as an example) you would choose the better one. Same with GtG, its a modifier.
There is nothing in the jink rules that says it stacks (at least in my PDF of seventh), and you would need something in there that says you can stack them. Jink text below to add to the convo-

Jink
When a unit with any models with the Jink special rule is selected as a target for a shooting attack, you may declare that it will Jink. The decision must be made before any To Hit rolls have been made. If the unit Jinks, all models in the unit with this special rule gain a 4+ cover save until the start of their next Movement phase, but they can only fire Snap Shots until the end of their next turn.

Thats my reading of the rule, but of course other people may interpret it differently.