My go to shit in the gi is Ezekiel chokes, you can catch them from almost anywhere including your opponents guard. Also if you can open up their gi and flip a lapel (i may be using incorrect nomenclature, the bottom of their gi) up and over one of their shoulders from inside your guard it makes for a really tight way to control posture and make your rubber guard even more effective. Being a brown belt your knowledge level is obviously several orders of magnitude above mine so i hope you don't mind my offering some tips, but i train in the gi a lot and thought i would share some of my better gi techniques. Good luck!