I've just replaced all my water hoses with silicone.
I've measured the outside Dia of the hoses off the car, which are as follows:
1 number @ 14mm dia
2 number @ 17mm dia
1 number @ 20mm dia
10 number @ 25mm dia
1 number @ 30mm dia
4 number @ 42mm dia
Matt.
P.S. just the cheap Mikalor not the fully stainless will be fine.