Mythos & Mayhem. Working on a few Mythos spell conversions. (OSR)

I'm working up a few of the classic Chaosium spells for our game.
I'm referencing CoC and CoC d20 for inspiration.
Got three worked up the last half hour and decided what the Hell let's post them.

Chant of Thoth
Spell Level: 3
Duration: 1 round per level
Range: Self
Adds a +5/25% to all checks, attribute and class ability, involving Intelligence.

Voice of Ra
Spell Level: 4
Duration: 24 hours.
Range: Self
This spell adds 1d6+4 (Max 18) to the caster’s Charisma.
This is also used as a bonus number of HD in calculating creatures affected by Charm spells.

Voorish Sign
Spell Level: None
Duration: Immediate
Range: Self
This is not a spell but a complex hand gesture to enhance spell use. Once the gesture is discovered or a teacher found the would-be user must make an Int check and a Dex check to learn it. Once it is learned it can be used at will unless the caster is under duress such as an attack, restrained, etc. In such a situation the caster must make a Dex check to successfully employ it. Using the Voorish Sign is a full round action.

It must be used immediately after being cast on a new spell.
For Non-Spellcasters: The Sign gives a +4 bonus to Casting Check of the next spell.
For Spellcasters: The Sign gives a +4 bonus to the Casting Check for rituals. For normal 'slot' spellcasting the spell cast by the spellcaster in the next round is treated as if it the spellcaster was two levels higher.