300CD first gear... slip?

[CDTurbo001]

Since adjusting the throttle linkage and Bowden cable on my '82 300CD the other day, shift behavior is much improved. No more harsh 1-2 and slipping 2-3 - under normal acceleration the shifts are firm
but not violent. However, after having pulled up to a stop in traffic, etc., when it comes time to move again I have to tip just a bit into the gas pedal, wait 1-2 seconds until the transmission seems to fully re-engage first gear, then I can move on and it behaves fine until the next stop. My initial setting for the Bowden cable was where all slack in the cable was out at idle, but no further. Tried 1.5 turns out and that doesn't correct the problem - haven't tested where the WOT shifts are as a gauge of cable adjustment, don't really want to run the engine that hard, that much until I can adjust the valves and check timing chain stretch.

Also, I checked the modulator line for vacuum leaks - held pressure fine. Also replaced the hard lines from the switchover valve to vacuum supply, and to the coupler leading to the transmission; it seemed the multi-connector on the SOV had become hard and was allowing a small leak. Removed the line to the ported vacuum switch/EGR as well. Did not test the vacuum signal from the SOV - as I understand it's supposed to vary with throttle position?

Any insight on what's causing first to partially disengage/slip until the pedal is advanced slightly?