Easiest perk farmers? Mossie, 38J, Ki-84, 109G2/G6/G14/F4, Spit9, Yak9s.
All those planes can land kills with relative ease in the MA environment with decently high ENY. The early war planes might be fun, but against even a mediocre pilot you're dead unless you have plenty of alt. these planes still offer a fighting chance against almost all planes.