Not to put too fine a point on it, but a band is only as tight as its weakest link. I have been to many a show at a blues or jazz club, or to charity events where the players have never met each other before and they sounded great, because they were all seasoned pros. I don't really buy into the concept of needing lots of rehearsal time to be in a "tight" band. You need guys who are all musically fluent and with great internal timing. A strict personal practice schedule, like the rest of your mates have is as important as rehearsal time. Both personal and group rehearsal are productive in different ways. I don't personally think one is more productive than the other, but I know which one is easier to arrange and knock out.