After the first signing cycle, any other player that is green will sign on the next cycle. Just make sure you've offered them a scholarship. If they are yellow and you've offered them a scholarship, then you need to read their response from your scholarship offer. That's the only response that matters. If he said that he is leaning your way but just needs a little more time, then there is really no need to throw more money his way unless you get another message later where he says that he is better off someplace else. That means that the other owner spent more money on him. If you still want him, you will then need to spend more money on him to try to get him to swing back your way.
If he is leaning your way but you just want to send him more CVs to get him to sign sooner, there is no way of knowing for sure how long or how much more money that will take. Some players hold out many cycles before they decide to sign.