I have already obtained a shiny roggenrola and I will tell you what I used so that you dont have to struggle with the process for yourselves. First things first, this will be an S.O.S battle so you will need to grind up some leppa berries (I got lucky and found it within the first 200 of the chain but you might not be). I would stock up on at least 300 leppa berries (2 leppa harvests if you have a maxed out isle aplenty, should only take a day with beans). This hunt will be done in Ten carat hill so that the mons are lower level and have a consistant movepool (earlygame moves also have a tendancy of having very high pp counts) of tackle, sand attack, headbutt and harden (the highest possible level gets rock blast so avoid having that one be the caller, its far more pp effecent if it has tackle instead). There are two major problems with shinyhunting this Pokemon, it has a high chance of having sturdy (that goes down as the hidden ability rate goes up) and every single one of them has sand attack (it only gets its 5th move at lvl 14, and it replaces tackle (I think)). So, what we need is a Pokemon that can both counter sturdy and the sand attack accuracy drop. Quite surprisingly there are several different ways of doing this (mold breaker with an infinite accuracy move, mega kanga with an infinite accuracy move, solgalio with sunsteel strike and no guard with a multi-hit move just to name a few) but by far the easiest and most effeciant way is by using Keen eye toucannon with bullet seed (sunseel strike has a max of 8 pp whilst bullet seed has a max of 48, far more efficiant to do it that way). make sure that toucannon has a single target move other then bullet seed or beak blast to function as a pseudo-false swipe (make sure that you have a mon that knows false swipe just in case) and finally roost. While doing the chain make sure to prepare to switch the caller after 80 turns, seeing as roggenrola doesnt always call for help (it does the majority of the time) and it can fail. You also want to make sure that the caller is below lvl 14, as it will always have the same 4 moves guarenteed, with tackle, headbutt, sand attack and harden you get a pp pool of 95 to deal with. whenever it fails a call make sure to restore pp if you are missing at least 10 pp on any of your moves, same goes for roosting if you are below half hp. if you have nothing to do on one of those turns just use the adrenaline orbs, they wont be consumed so long as you have already used on previously in battle. hopefully this helps all of the aspiring shinyhunters there who like the blue crystal boy better then the orange one.