Subscribers cannot be added manually as Udimi filters are very strict. Also you will notice that the IPs are captured by udimi and available for you to see..
It is important to run an aggressive campaign immediately following the solo ad run, otherwise your email maybe lost among the emails received daily by most inboxes.
As yourself put it, you want to be remembered.
I wanted to know when the solo ads runs, Do the subscribers opt in themselves through the solos ad link that goes to a capture page or do the owner of the list add them to the capture page themselves? The reason I ask I notice a lot of the people that optin claim they never optin to no capture page