Depends on a lot of things
My basic regieme in a 300
Pre solo stage up to 10 - 15 kts if hovering, basic autos, circuits up to 20 kts
Nav stage up to 25 kts - really shows drift !
Solo nav up to 25 kts, but max 20 kts on field
This is not gospel and will depend upon everything already spoken about.
Towards end of course take people up in 30 kts just to see !