Which H!Jakob ??

+atk is his best boon and personally what I would go for, it's especially useful for his brave bow build.

The best for me is the -hp +def
With the Guard Bow+ it's the ultimate tank.

Depends on your build, Jakob is an armor unit, lets not forget that. So, a -res o -def bane isnt great either, so just go for the +atk and maybe you can get a better one down the line, id prefer to get neutral than sacrifice bulk on any armor unit. But thats me, you can still give him buffs and such to increase his res, but you will need to get a bold fighter to use it to his full potential.

Go +atk -res, and refine his resistance to fix it.

By far the +Atk is better, +Atk is his best boon, but beyond that you never want to have a -Atk or -Def Jakob.

Mine is +Atk - hp, and I hope i can eventually get a +Atk, -Spd.

But your - Res was is good, I would merge the other one into him, and just give him the Dist. Defence seal as well as eventually build him into Brave Bow+,DeathBlow,Bold fighter, and Ploy or Armor skill