Solar hot water system (boost) timer (times of day, how long

Hi all,

Our house has a solar hot water system on the roof. As a family of 4, we often run out of hot water, particularly in the winter months. The system has a boost setting which i can set the time of day for it to come on.

Can anyone advise what sort of schedule should i set on the timer? Currently, I have it set for a few hours in the morning before we wake, and a few hours in the afternoon before showers/baths etc..

Thanks in advance!
Justin