I forget who said it but you don't need less farmland you need more storage. Put custom stockpiles for booze and food by your dining room, barracks(by the fort entrance), by the forge living quarters, hospital, gulag, cavern checkpoints, Panic room, control room, and then theres the excess prepared meals stockpile by the depot for trade. More is a good thing. Training the processing skills {Milling, Processing, Wood burning, Spinning, etc.} can only be beneficial. Set up stockpiles for mass manufacturing dwarven syrup. Quarry bushes are important for those 10k-20k+ roasts. Large dimple cup farms will help employ lots of millers as well as keeping all your cloth dyed. A robe made and decorated with all exceptional dye, cloth, and image from pig tail fiber can reach the latter 2k's.[Custom stockpiles to hold them near the depot] Trade for leather and you'll push it higher probably other things to improve it as well. No offense but 120 dwarves can quickly devastate your food stores if a siege gone bad or a disease epidemic halts production. If you REALLY NEED to do another industry then work up a stockpile system to manufacture gold or better statues with quality metal and gem studding.
Tl;dr Get more Dwarven wheat, longland grass, and a whole hell of a lot more quarry bushes, sweet pods, and whip vines. Your milling Marksdwarf hauler-reservists demand it!