Close your gap by leveling just 1 mastery. When you hit 42 used cursed heart and get rid of that mastery you added. bam, back to 9gap
I would personally farm at 52. Plenty of Penons to go around. Dead ravine, bandits, yeowa, and red scorps are alright, but if you kill them too fast you gotta wait for them to spawn. Bunwang are really good though, but at 42 you gotta be careful cuz theyre agro. At 52, Theres ALWAYS penons around. If you decide to farm at 52 then id say level with 3-5 gap untill then just so you have some SP to spend.