Hi Wolfie its always difficult to know the best time. Mornings around 8.30 ish seems to be really busy but so are afternoons. And of course it depends on the weather also. Birds don't like wind!
What I did was, seeing as I like watching the birds anyway!, do it several times over the weekend and you will get a pattern of the best time, bearing in mind the weather. You can send the figures for when your garden was most active with our feathered friends.
hope it's enjoyable for you and Mrs Wolfie, it's what you do anyway ! You may even see a different species visit you.