score:4
On the Royal Collection Trust website (accessed 2022/05/06) there is a gallery of images of a different set of armour, titled "Armour garniture of Henry VIII for the field and tilt". One piece of the armour has obviously been adjusted:
To allow for the King's increasing girth, the backplate of the armour has been extended by 5.1 cm at either side by the addition of plain plate secured with rivets. Cylindrical studs under the arms designed to receive the hasp projecting from the breastplate have also been adjusted twice: by about 2.2 cm on the first occasion, and a further 3.2 cm on the second.
So these sets could be adjusted and extended, but much less likely 'taken in'.
So in the case of 'sharing', it seems unlikely the larger person couldn't wear it without a permanent adjustment.
As for wearing armour too large for you, to a certain extent you can wear sightly more padding.
In this case however it was not sharing that took on place, or even inheritance but simply an adjustment to make sure the armour truly was fit for a king.