Not too shoddy... pardon the pun!
Only looks like some minor tweaking, mainly what Spotted has said, re quarter 'scooping' & bevelling. It seems like you're using the sole plane as your basic guide for wall trimming - which I agree with - except at the quarters.
Looking at the pics, yes, appears he is a tad higher medially(inside) on that foot. I don't understand why your farrier would then advise you keep the lateral side shorter, but perhaps I misunderstood what you/he means by it.
Generally re imbalance of this sort, I'd basically trim to balance in relation to the (live)sole plane(seems you're doing) & let the foot do it's stuff, rather than trying to force any issues. This is because it may be a body issue, of which hoof balance is just a symptom, it may be due to injury or conformational deformation, it may have been a lifelong problem of a mature horse, so 'fixing' it may cause problems.... Confo shots & front-on of that leg, rads & knowing his age & use would give a better idea of whether it can/should be 'fixed' or left as is.