Microbiologylover

I hope someone can help, I've just conducted my pilot study for an experiment testing the effectiveness of hand sanitisers on killing the bacteria e.coli. From the pilot study I've realised that I will need to have the exact same amount of each solution on the sterile paper disc that I place onto the agar plate. Obviously some hand sanitisers are gels so its not easy to get them to fully absorb into the paper disc. Does anybody have any advice on how i could ensure that I have roughly the same volume of solution on each paper disc? Thanks in advance!!