Stratorat,
As I read your initial post, I have to guess, but it seems to me that you have the default closer settings in the strategy page, which is to maximize the closer rule. This setting may limit Fingers only to clear-cut closer situations, and so Hiller might end up as the only available option for Hal in tight situations that don't become a "closer situation". I should add Strat has a definition for "closer situation" in the rules (roughly, any 9th inning situation where the winning run is the circle deck) that is different than in MLB (roughly, any inning situation where a reliever has to protect 3-run lead). I'm pretty sure that the "maximizing" activation on the strategy page refers to the Strat closer situation, so the main impact is that he will limit the closer mostly to the 9th inning.
I set the following pitchers to F8:
Excellent starters
Super reliever
Closer
Dedicated Mopup guy
Everyone else I leave blank.
I never use slow hook. I rarely use quick hook (and never on a pitcher with F8 set).
I leave closer setting to Normal under team settings.
For 20XX, I do the same except that I sometimes use a "quick hook"+F8 when I feel that my second best reliever is only slightly worse than my best reliever. Also I don't specify a F8 role to the dedicated mopup guy. The main reason is because I feel that Hal deals cleverly the bullpen role in mopup/nonmopup situations. As long as the mopup situation is maintained, Hal will not remove the mopup guy, whether he is set at F8 or not. But if my team comes back and the situation changes, not setting a F8 gives the freedom to Hal to use the other settings and not stick to the mop-up guy.
However, my first year of ATG experience forced me to use other settings in the upper cap leagues. Main reason is that, in those leagues, I want to avoid at all cost a reliever being on a lower F fatigue state, and using a setting like F8+quick hook to a top reliever brought too many at-bats with lower F state. Depending on the depth of my bullpen, I will sometimes use for a top R3 reliever the following "slow hook" + "max 2-3 innings". Since the reliever is R3, the lower F8 will almost only occur in the third inning or beyond, and the "max 2-3" innings setting will usually force Hal to remove the reliever has pitched three full innings. That said, this setting forces me to have at least 3 studs if I use the quick hook on my starting pitchers.