My apologies for the delayed response. I was confined 2 weeks (prophylactic) and unable to go out for the components.
But now everything is back to normal and I replaced the rectifier bridge and the electrolytics with proper voltage ratings. There is no improvement, the results are similar to the ones reported in post #55.
I think we've done all that is possible, which taking into account my expertise, was a lot.
The result is quite good, so... I'm moving for the next one
I would like to thank you for all the patience, for all the help and guidance.
Tomorrow I'll make a video to let you see the final result.
Kind regards,
Diniz, from Portugal