I have a problem with the overall conception of the COP since I don’t feel we don’t all have the same understanding:

To be efficient, how long should the program last for each mentee????

Shall it be continuous for each mentee????

Do we have the ability to take the travel support of the mentor and give it to another mentee????

Is it important to have more mentees with shorter mentoring period and less F2F meeting attended????

My suggestion is to have each mentee participate in at least two meetings in order to allow for some continuity.  

Yes, you could use the travel support for two mentees and identify a mentor that has funding from elsewhere.