For what it's worth I honestly reckon you'd pick up just as much new work knocking from say 6pm - 8pm, when people are actually at home
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To be honest I'd knock one week and on the second week work during the day and knock in the evenings for the following week. Keep doing this 'til you've built yourself a full round. This way you're earning as well as canvassing; and you'll probably pick up more work whilst you're out cleaning; neighbours, friends, etc.
Honestly mate, knocking during the day isn't that good; the type of customers you want will usually be at work.
Just my opinion, based on almost twenty years experience.
Good luck; unless you're working in Plymouth