Making a jointed arm, like a clock hand but w/a {2nd hand/pointer} at the end the hand, so basically an arm.

AS MODELED, these would rotate only in the BANK plane. Since I'd prefer to simply use IK and a goal null, I'm wondering: do I have to reset the as modeled position of the two 'hands' (really, an upper arm and a forearm in a regular character rig) so that they are working in the HEADING plane, or is it workable to leave them as modeled and use IK in solely the BANK plane?

Tnx. My IK experience is basically zero.