For most if not all ISPs, using a purchased email list is against the TOS. It doesn't matter how targeted it is. You have not stated that you have a purchased l

For most if not all ISPs, using a purchased email list is against the TOS. It doesn't matter how targeted it is. You have not stated that you have a purchased list, but I'm assuming it is from your wording. You should contact your ISPs data security department(not tech support) and ask them to advise you on mail limits. Typically these are based on mails per hour. Im not suggesting you send the mails, because I think it's a bit tacky for a quality product, but they will best be able to answer your questions. Also be aware that the number of emails is not the only way you will be labeled a spammer by an ISP. The amount of email just triggers a port filter and equally or more important is the nature of your mail, the source of the addresses and the response of the people receiving it. When I was doing data security and TOS work for an ISP, spam complaints meant us cutting your service off. People hate unsolicited email. Find another way.