Just a question to fellow GMs: stat-wise, how would you handle spells that increase one's strength and which description is "your strength is doubled/tripled/quadrupled"? I'm not talking about combat purpose (where it's clearly stated that you gain a damage multiplier of x2/3/4 et OB bonus of +10/15/20) but rather for other skills involving the stat, or even a pure stat roll.
Just did a check via Spell Laws (RM2, RMSS, & RMC) - specifically in the Monk's Body Reins spell list (since that is the only core spell list that contains the Strength spells) to see how each version words the spell.
The "doubles caster's strength" only appears in the RM2 version of Spell Law, and given the actual functions of the spell, I would say that it is basically nothing more than flavor text within the spell's description. Meant to evoke a visual image, not be an actual description of how the spell works.
RMSS just says that it doubles hits dealt and gives the bonus to OB.
RMC says "increases effective strength" and then goes on to the spell's actual effects.
Looking at all three versions carefully, and considering the actual effects of the spell (and its various versions at higher levels), I would say:
[orule=Official Ruling on Strength Spells]
The actual effect of the spell is that it generates a magical field around the caster that aids in any maneuver that utilizes Strength. In combat, this results in an increase in the amount of hits dealt on the attack tables (this excludes hits dealt from the critical tables) and a flat bonus to any action or maneuver that utilizes Strength.
Thus, the lowest version of the spell which gives a +10 to OB would also apply a +10 to any other skills or maneuver rolls that utilize strength.
[/orule]