Welcome to the site !!
It sounds like your Clutch Basket is grooved , this would be the cause of the inconsistent feel , and the "grabby" feeling you are experiencing
This is what a worn clutch basket looks like (below) ....... You can try to file the grooves down , but this will only buy you some time
as you can only do it once before the basket becomes "sloppy" , it will have to eventually be replaced , but you may get a season or more out of it depending on how you use or abuse the clutch , when you do replace the basket , install new clutch plates and disks ......... As far as the oil , what most of us do is run a full quart in the tranny side , and use the recommended amount in the engine side , doing this is not so much for the clutch , though it does assure that the clutch does not run dry , it is mainly for keeping the tranny gears submersed in oil as the cavity for the gears is very tight and the spinning of the gears causes cavitation and some have had 4th and /or 5th gear break due to overheating or bearing failure due to lack of oil , mainly if used in the desert or dual sporting where you are running in high gear for extended periods , but a lot of us run the full quart even if we don't do that , it wont hurt anything , and it gives a little insurance that the clutch wont run dry or overheat , as may be your case ....