I currently am training farming too, and livid farm is great. The spells you get are awesome, and the 30k per hr xp in farming really adds up with farming normally in between.
After my slayer fights I find a way to hide from the monsters I'm killing and then tele to lumby. After I go straight to that slayer fairy bringing my dramen staff for every task. :)
I've always put my ads on low detail and it usually works fine... Sometimes if you leave your computer on the rs login page for like a few hours the add would disappear completely :D or for only me i guess :?
I think that maybe in the near future there would be more different monster drops for high slayer... like they will release more slayer monsters making high slayer very helpful. I'd say go and train it. :)
I've found tons of gems before and made them into jewelry :) I think thats the best thing I've got... I don't usually look into general stores for things though :?