Re: followpost gels
BTW Derek, the current tour of "In the Heights" uses a ziploc baggy for one of their followspot frames.
If the followspots you encounter have the same color temperature as your 575W lamps (assuming 3200K), you'll just need the R60. If the spot is an arc source (likely) I'd take R3410 1/8CTO and add as many layers as you need (probably 4--giving you 1/2CTO). Additionally, R3318 1/8MinusGreen (probably one or two layers) can be used the same way and will be beneficial if there are cameras.
BTW Derek, the current tour of "In the Heights" uses a ziploc baggy for one of their followspot frames.