What size prey

[Gio]

10-15% of the snakes weight is a good guide.

I like KMG.

Pythons can take larger prey than boas in the young stages. The visual rule of slight, or noticeable lump is a decent one to follow if you are not weighing things. Royals in some cases will pick a season to start refusing food. It may or may not ever happen.

Feed conservatively until you think a jump up in size is doable.