I wanted to start using pooled HUVECs in my expirements to reduce the possible variations in cell phenotype and behavior due to the different genetic background of donors, but I'm not sure about the exact method to do it? Can anyone explain this to me?

Do I need to use the same number of cells from each donor? same passage?

or is it a matter of taking 500 microliters from each cryovial and just mixing them? and then can I return the cryovials directly to LN2 (remaining 500 microliters)?

Thanks for help,