just progressions?

after reading Coach Sommer's book "Building the Gymnastic Body" I'm unsure on weather the exercises in there are specific progressions, as in once you can do a harder variation theres no need to work with the easier variation?

i ask because there are so many diferant ranges of motion for pressing/pulling etc would it be benificial to do a cycle on an easier varation but with added weight more reps etc?

I would say that there could be uses for going back and doing easier progressions with added weight. For example, many of the exercises incorporate core strength elements at the same time as requiring upper body strength. There may be a reason that you don't want to work your core (injury, rest, isolation?) so you could do something like - tuck front lever rows with weight attached to harness. This would work the upper back and bi's without stressing core so much, if for some reason you wanted/needed to do that.

You may also just simply not have the core strength. Weights with easier progressions on FL can at least help build the uper body strength while you work on the core, but if you're doing HLL and body levers it shouldn't be an issue.

Earlier progressions are good for warm up once you are too strong to benefit from them as the main working sets.

This may seem like a rather stupid question, but where would you put the weights in the easier FL variations? At the ankles, I'm guessing.

I would use a climbing chest harness.

wat about with the fundemantal bodyweight exercises without tuck, straddle etc variations? for example xr bulgarian dips are the last dip variation but feel completely different to korean dips wich are a couple of variations earlier. is there a need to train korean dips if you can do xr bulgarian dips ?

Sometimes your body and your brain needs a break from performing the same movements, and variations of a exercise are warranted to prevent staleness. That's another possibility that you could use the other progressions for.

Another one I can think of is for a deloading period where you decrease intensity.

Yes, because if you look at the multi-plane movements, one is an extension of the korean dip where you go down to back lever and then all the way back up. It is always good to do at least one set of each progression once a week as part of your warm up sets, and perhaps more if you feel like you are getting something out of that movement that is helping you. Everything is useful.

As well, most people won't have access to a single rail.

If you were weighting the front lever, I would use a belt since I don't have a harness. I wouldn't bother weighting a back lever. Just move the arms wider.

If I were concerned about covering all possible area's of motion (as in: hands in front/hands behind/to the side/etc) I'd use either Pyramids, or a modified PTTP as detailed in the programming section of BTGB. Of course heavy reliance on multi plane movements is probably a good idea also.