Hi, we do lot like this; you can not force to avoid spam, it's depend on setting user may have it in inbox.
are you expecting, dynamic data to be part of your email body? Do we have to use SMTP of yours or you need it from us.
I can create a software, and you can send unlimited emails by buying SMTP Service. if you are interested, we can talk about cost.
thanks,
Stalin.
919643306349