Blimey - this is tough; haven't tried a 'Printer's Devilry' before - don't know if Araucaria has done one before but I know AZED has.
After 1 hour on and off I only have 4 of which I am confident - 9ac, 24ac, 18d & 21d.
For 21d I agree with cmk @26 and ixion @38.