Mondays if your bi inclined.
Tuesday through Thursday it just depends on who turns up on the day. Can be great but also can be quiet.
Fridays can suffer from the evening effect because they are very popular and people turn up later.
Suggest you decide when you want to go and ask for 'volunteers' to meet up with you there.
I'm sure there will be a few 'youngsters' who will turn up to assist you in your endeavours
G