Most countries put a stamp in the old passport that reads something along the lines of:-
"This passport has been succeeded by passport (number) and may be used when presented with succeeding passport for the sole purpose of presenting any visa that may continue to be valid"
Again more 8ollocks from someone with a meagre understanding of the world. My friend is responsible for keeping your precious roustabout rigs on station. For that he needs a Master's ticket not a survival suit and a helicopter ticket.
As you said
Sadly a lot of small businesses selling such stuff have disappeared and been replaced by condos. Try your local market for a store selling buttons and notions.
The 120 is only for motorways/roads with no junctions or U-turns. The reduction to 90 when there is a U-turn is a weird asian interpretation but correct.
Anyone who has ever owned a toy gyroscope will know it is the wide bit at the equator that will have the most effect not the small diameter bit at the top.
The core on the other hand will have an effect and no amount of electric cars will effect that change.
Well, it is a bit late now, horse bolted and such but, you should have reset the code before you started using it.
What you have done is akin to locking a scooter key under the seat. You will only do it once.