A Few Questions:

I've been mining only a little over two weeks now, and I had been using GUIminer on scrypt mining with a 290x Tri from Sapphire and an old sapphire 6850.  I got my hashrates to the range scrypt sites recommened, but a strange thing was happening--my 6850 was making more shares than my 290x.  I'm assuming after further reading this was due to HW errors, but in GUIminer i can't see those. 

Enter me buying another 290x, removing the 6850, and setting everything accordingly in GUIminer (after replacing the cgminer it used for scrypt with the scrypt-N modded cgminer), my hashrates for my 290x cards were both sitting 462 each steadily.  I was happy with the hashing rates.  Last night was my first full night to let them run full speed.  The 290x which my monitors are plugged into, however, only put up about 70 shares the entire night, while the non-display 290x put up almost 700.  They were both hashing at 462kh/s.  both using the same settings: 970 core/1450mem OC.  I've got 12GB of memory on my rig so I don't believe it's the memory bottleneck many encounter, and I've got a 1000W powersupply, which for 2 290x cards should be fine. 

Is the only likely cuprit HW errors?
 thus i need to start using cgminer/cgwatcher directly so I can track that more easily?
in general, is more Khash/sec=more shares=more vertcoin?