considering you wont need them unless you are doing TFB HM, i dont see the issue.
If you are doing TFB HM, you should have Denova on farm....
Assumeing the above 2 are true, you can get enough comms to make this in about 4 weeks if you include LFG daily's and LFG Operation weeklies.
that's gonna be at least 5 to 6 weeks for a lot of people because they won't always be able to spotlessly clear every operation that drops BH comms all the time. I've been farming for a long time now only have around 270.