Yes - SAE 30 or 40. That's NOT 10W40 - which is effectively 10 grade. You should get it in a small can at a motorcycle place - certainly Tesco have 30 grade for motor mowers ion small cans. Maybe a good starting grade.
No, quite the opposite - because it effectively damps out the movement and stops the suspension banging the bump stops - THAT'S when the suspension goes solid !
A 250ml bottle should do it.
Find a plastic syringe. It makes filling a doddle. If you try filling from a bottle its hard to pour accurately and you tend to get an airlock and it all spills out.
Older and more confused than I could ever imagine possible.
Well why does a modern car with soft coil spring suspension float fairly comfortably over road humps at 30mph and a Minor with hard torsion bar suspension feel as though it is hitting a wall at 15mph?