To get my females to ovulate, I don't really use the paper towel trick. Instead, I just put the females one at a time into the male's tub (with him in there and with me watching). That tends to get the hormones flowing! I only leave them in for about 5 minutes though.
personally I wouldn't put them all together at once...esp if they have never been housed as multiples. Just in case any of them are aggressive. You can try all at once but watch for a while and see how they like each other. I like to leave my male with one female for a week then let him rest for a week then another female for a week and so on.