While getting from 1-50 only takes around 35 mins with this method, after lvl 50 it gets stupidly slow...The highest i have ever plvl'ed anyone was to lvl 52 before i said fck this and ran out (leaving them to get swamped by bugs, muhahaha). If you can afford it, buying dog meat is much faster and assuming there are few people around, a few lucky pots and farming dogs is quite fast, though if i ever went back there then I would still be doing 3/4 of those quests (not dogs) as i'm cheap
In my experience, and unless you have a good supply (15+ stacks) of dog meat handy (plus DRTs), once you've hit lvl 52 or so it's very definitely a long slog to lvl 60.
And that's on a single class. If you're trying to level two or three classes, have fun.
I haven't been up to the Gardens on Osha recently, simply for lack of time, so I don't know what the area population has been looking like recently. On your server (Thalia), things may be rather different and there are fewer people farming the dogs.
There's at least one person on Osha who used the bug method to plevel an alt all the way to 75 (two classes, I believe) in about 5 hours. That's not terribly unreasonable, but I'd bet that their hands were really hurting afterwards. I have no info as to how many times the alt may have died due to a botched kite.