You can do as Hutch said, but even turning the limb out isn't always necessary. All you have to do is squeeze the riser and cable together and this usually rotates the cam enough to get that "hiding" screw. So you hold them together and loosen the screw with the other hand. In a pinch, if you can't hold it long enough you can use a good sized zip-tie around the cable and riser till you're done with the mod swap. Now. if for some reason this doesn't work then do as Hutch suggested.
As far as the modules are concerned? Look at the Technical Specs on Martin's website. Not putting you off here. Just trying to treach you something. The Saber goes from 25" to 30". The f1 mod is for 25". f2 is for 26" and so forth. Don't ask me why but somehwere in the middle they will not use the f5 or f6 mod. Don't worry about it. Use whichever you need to get your draw length right. It doesn't matter what the draw length is so long as it fits you. Also, as with almost all bows, don't expect it to measure what the charts say. Most bows draw about 1/2" or so longer than what the charts say. Just make it fit.
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