After a whole bunch of looking I'm getting pretty sure that warlock spells are segregated between grimoires and daggers, with staffmods of 'weapon' type only spawning on daggers
From what I can tell, all skills are available on daggers, just grimoires restricted from having weapon spells, namely Hex Bane/Purge/Siphon, Echoing Strikes, Blade Warp, Mirrored Blades. Not sure about levitation mastery since its too low tier to spawn in hell
This is a shame, because a Splendor in a +3 hex siphon tome would be the best in slot option for PvM warlocks on most builds as CTA swap, instead of the normal spirit monarch. You'd trade off -1 BO in exchange for saving 3 skill points on hex siphon (and getting +1 to it overall)
So yeah no way to save skill points easily, not unless you want to swap in a dagger, though magic builds can use a void with +3 abyss / +3 hex siphon.

Make your CTA in a Dagger yeah
Too bad it isnt "RalIstOhm"

Shame there's no 2 handed 5 soc daggers

:S

Yeah I've done both some searching in cows/etc and searched through pages of trade forum tomes/daggers being posted and I'm pretty confident all the spells spawn on daggers unless there's some dumb exception, and none of the "weapon" skills spawn on grimoires, and blizzard previously patched the overflow safeguard that let you spawn forbidden staffmods ala +holy shield on a scepter. So you are forced to spend 3 skill points to get hex siphon on all builds, and should dump 20 points blood oath on all builds.

2 handed dagger, why has no blacksmith ever thought of doing that ?

2H'ing my corvian greatknife come at me

Giant’s Knife
Dagger type
2-handed
46-98 dmg
WSM: 20
Max 5os
Str req: 240

Durability: 8 hits total