custom sg rulez , lf a bit of help

I think that's the most you can do with SGtools. There is no achievements rule definitions on it.

is there any way to be more specific to allow only those who finished the game, or spend a minimal amount of time in the game or ??

I have seen some some GA creators only inviting/giving the GA link to those users having specific achievement for the game. For example in this case you can give link to those players who have "Polarized" achievement, which is story-line achievement for completing the game.

I don't know about sgtools, but you can do it with a lot more work by creating a thread and asking people that qualify to post a link to their achievement page. Then you can check each person and either add to your whitelist or create a temporary Steam group that they can request to join and limit the giveaway to the group.

Or u could just WL people who wants to join ur GA by checking their achievements.

Maybe you could do the first part via the sgtools custom rules.
Get participants to comment on an old GA that's linked in sgtools.

Then check the second part manually and send the links to those who pass the rule you want?

you don't know the lengths some go to idle another win (like cheating achievements, or speedrunning games to finish them). ¯\_(ツ)_/¯

the safest is to manually check for achievements and invite people to a group, or add them to your wl.
takes more time but you will be almost sure that person is gonna play it.

the Playing Appreciated group?

Apparently there is also a way to fake achievements (what for? I do not know) so even that's not a sure thing.
Good luck with your quest though.

Sorry Mr Green, the only way to be sure of anything is cloning yourself.
But who would want that?

Anyway, even if you wanted to create a strict ruleset, the problem still remains that the winner may still not play the game.
And let's face it: that's what you want more than anything, right?