You got the numbers almost right but you're on the right track.
1.) Remove the 330K ohm resistors (one at time) and replace with 220K ohm resistors. Leave the one end (that's being used as a common tie point) up in the air for now.
2.) Replace the single terminal strip with a dual terminal strip. The white wire attached to them comes out and gets coiled up next to the DUAL BIAS CAP FOR NOW. This will end up as your HOT WIRE for the IBAM BOARD, or remove it and solder in your IBAM HOT (POS +) lead to that point. You'll have to loosen one side of the transformers and undo completely the other to get 4-40 x 3/8" screws in the old rivet holes to attach the new terminal strip.
3.) With TWO NEW Terminal strips installed, place the free end of each of the 220K ohm resistors into a separate terminal and run the IBAM LEADS for each tube up to the terminal strip. Attach the IBAM LEADS to the 220k ohm resistors (one per terminal).
4.) Tighten everything up (transformers), and make all solder connections.
You're done. Adjust as needed. remember each adjustment on one tube is somewhat interactive on the other tubes. So keep at it until they settle down. Should be about 3 series of adjustments.
When you change to the 220K resistors, also change the coupling caps to .068uf. That's the ideal value to keep the timing constant of the R/C network. But if you already have .1uf caps in you'll be ok. The changes aren't audible. This upgrade is also warranted for old tubes as the 330K value is too high even for them.