I believe the demand for lawful money isn't quite on point. AFAIK one is to #1 Redeem a bill for lawful money or #2 denominate transactions in lawful money. You start changing the verbiage too much and getting away from the applicable statute they might spot your error and come for "blood".

To reiterate: the checks would be redeemed for lawful money. Demanding lawful money isn't in the applicable statute.