further testing done. car sat for at least 5 hours in ~15 deg C weather since last time i drove it and experienced the problem of the car losing its smoothness rolling from a dead stop.
this time, reverse was great. so was engaging 1st then 2nd then 3rd etc
everything working beautifully. taking it to 6th, downshifting to 4th, giving more throttle taking it up to 160kmh or so and back into 6th.
let the system downshift from 6th to 1st at lights. roll from 1st back up to 6th. no issues.
HOWEVER, when i get back to my neighbourhood, i decide to stop, and engage the car from second. immediately i could sense a difference. and sure enough when i tried engaging 1st again and moving the car, it went back to being a bitch all jerky and jumpy.
so, i am guessing that as long as i move the car from 1st, i'm golden.
as soon as i engage 2nd from a dead stop and move the car from there, the problem comes back.
this could however be a heat-related issue (car warming up), but i highly doubt that
i asked my father if he remembers whether he tried engaging 2nd from the dead stop when he first drove it last time. he says he could have done that but cannot be 100% certain. i believe he did.
let the car sit for about 25 mins, tried it again, car was still warm - coolant temp was around 70 deg but i tried anyway and reverse/1st/2nd were NOT smooth
so what is to follow:
test the car tomorrow again once it has sat and became cold, or had time to reset everything - whichever is the reason
i am 85% hopeful and expecting that the car will shift fine from 1st and reverse and all that. and i will try to NOT engage 2nd from a dead stop the whole journey + even when i come back to my neighbourhood.
will test the car again, same day, 30 mins later, same thing.
after tomorrow, if i am feeling cocky i will test it a third time and when i am back home i will engage 2nd. i am expecting the problem to re-occur
if it does, i will have identified the issue and will learn how to set the car/clutch to roll from 2nd just as it does from 1st and be done with this matter hopefully for good!
wish me luck

keep you posted, and thanks guys