I have had sagos growing out over walkways or porches in the past that I have repositioned in the same location to redirect the growth. Often times you will barely need to move the plant, you can spin it, or just lean it a little and palms are one of the few plants that don't look bad when leaning. I have on many occasions cut all the fronds from frost damaged sagos and they have always come back. As far as when to do it, the only difference between doing now or in the next two months would be appearance. Would your client rather look at a completely trimmed up crown, or a bunch of dead fronds?