Lucky! This was done on level 34 with a swordsman build, some additional talents put in Quen (2/2) and Magical Vigor (2/2), and as far as my knowledge goes, with all the best items equipped as well. Still a tough fight!
yes, but you have to make special potions before hand and have to drink them before a battle. And these aren't like immediate health boosts, it only really slowly gives you back health, like maybe 1 hp a second.