MACO only mentions 12(yellow), 22(orange), 25(red), 29(dark
red), 70(very dark red), 88A, 87, and 87C (Black, IR
transmitting) on their website...  No mention of 89C on, nor in
my "filter bible": CRC Handbook of Chemistry and Physics, 62nd
edition. There is an 89B, with 50% transmittance at 720nm,
however...  The 50% point are (roughly):  25: 600nm 29: 620nm
70: 680nm - narrow band filter 87: 795nm 87C: 860nm 88A: 750mn
89B: 720nm  So 87 and 87C would be very dark for MACO 820,
almost totally black for Konica IR750. 89B looks more promising,
and is equivalent to what is sold as "R72". 70 would give about
the same results as 89B with IR films - except Kodak HIE, where
it would cut off some of the far infrared.