MTB,
To be honest, I fish the upper for more fish & I fish the lower when I wish to catch big fish. That being said, you can do both in the same day. BUT, the K lakes are notorious for being spotty, so one day can be on fire & the next day nada. Still, it is a great place to fish. The fish from both lakes are awesome, but like I said, the big boys are downstairs in the lower. They're just a lot harder to come by. As summer progresses, things change a lot in those lakes too, so what works today will not necessarily work next month or the month after.