When it comes to lead nurturing, the importance of getting the timing right is not necessarily about which day of the week and what time of day you send the emails. It's about how quickly you follow up with your new leads in the first place.

Check out this stat from HBR:
"Firms that tried to contact potential customers within an hour of receiving a query were nearly seven times as likely to qualify the lead (which we defined as having a meaningful conversation with a key decision maker) as those that tried to contact the customer even an hour later—and more than 60 times as likely as companies that waited 24 hours or longer."
Article here: https://hbr.org/2011/03/the-short-life-of-online-sales-leads/ar/1

In other words, that first email in your nurturing campaign should be sent nearly immediately, or at least within an hour of the conversion, when you're still top-of-mind for them. If you have a sales team, you should also set up an automatically-triggered email notification to the appropriate sales rep that a new lead has converted and should be contacted ASAP. (Every sales rep I've worked with has been THRILLED to receive these notifications.)

Lastly, if you are looking to get a sense for what days/times work best for email engagement, and your list is sizable enough, you might consider doing a 4-way split test, sending the same email content to each quarter of your list across 2 different days and 2 different times each day. This will give you even more data to work with than your typical 50/50 A/B test.

Let me know if you'd like to continue discussing strategy around setting up your nurturing campaigns. Happy to help!