How/where to add VFO to Midland 13-898B`

I have a very nice working (other than clock) 13-898B that I would like to add some of the popular SSB channels (36, 38, etc) and not sure how to proceed. Looking at the schematic it seems that a crystal would need to be removed and the vfo output inserted into where the crystal was. I also see the crystals have a trimmer across them and I'm assuming that the trim-cap is just there to tweak the crystal frequency.

Do I have this about right?

Thanks,

Justin B.