great guide, man.
With VTC/PANDA it's actually pretty wonky to find a sweet spot. I start with 1000/1500 core/mem and increment up and down a bit to find the sweet spot. With vanilla scrypt, any increase that remains stable is bonus, but with nscrypt, I've found that going up can sometimes lower hash (without even throwing HW errors). I tend to hover right around 1000/1500 on my rigs, which run combinations of ASUS, MSI, and Sapphire (all 280x).