I agree that he is a viable jungler and let's be honest... you dont need to practice jungling with him. Pressing q and autoattacking minions mindlessly doesn't make him any harder to play than any other jungler. I might have missunderstood you but it sounded like Darius
hard. It's more a thing of understanding the jungle and knowing what to do which you need for every jungler
About the sightstone: I really like the item but I'm not sure if it is the right item to snowball you ahead. It wont make your jungle faster and neither will it make you a lot tankier. It is an amazing item to stay ahead once you managed to get an early lead but even then I'd only buy it if your lanes are too stupid to ward for themselves
although you asked them to. You dont need to ward their jungle all the time. 1 Ward all the time (talk with mid so both wraith entrances are covered or just ward the other entrance when one is warded) and an occasional ward at buffs when you know buffs will respawn are enough. That would be an average of 1.6 wards per 3minutes [1 permanent, 1 ward every 5min] or 6.67 gp10 (let's say you ward things which are not really necessary and round it up to 7gp10 => you need 16min and 40sec to have the sightstone pay off. A very long time). Looks nice but considering you will fall behind in gold as a jungler and it doesn't really help you do your job (stand in the frontline, soak some damage etc) which would make forcing objectives easier. I guess thinking about it I'd hardly ever get the sightstone as a jungler.
PS: My point of view might be totally wrong due to exactly 0 sleep. If i'm wrong tell me