Wrong lens on the Rolleicord for portraits. You want a Triotar. Much nicer IQ for that job, as it's sharp in the center and sort of peters out in the corners wide open. Prettier bokeh too. You can do some googling, but trust me, the Triotar was the go-to lens for portraits back in the day, and still is at my place. Yes, the Rolleicord screens are not the brightest, but there's a magnifier, yes? I never had any trouble focusing mine even w/ my 63 year old eyes, and it's child's play to swap in a good brightscreen if you wish. A cut down RB screen brightens things up considerably, and you can buy a new mirror on eBait for $8. But I would keep the camera and lenses that you have (better focal lengths for portraits) and buy a beater old 'cord w/ Triotar to see how you like it.
The shot below was Tri-X in D76. I forgot that the developer was full strength and used the longer times for 1:1, which gave things a pleasant bite and that old time Tri-X grain. This is just a scan of the neg. The prints have much softer grain. Now I use those times all the time w/ uncoated lenses to give them a little more contrast. But I haven't used Tri-X or D76 in a while, preferring to shoot Arista EDU Ultra 100 in Mic-X.
It's amazing how small and light the early Rolleicords are, especially compared to that RB67 of yours.
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