Accurate thoughts on the main line being heavier than your leader... once you start using dipsys, you'll quickly understand how much pull/tension they have on a rod/main line!!!
Honeslty it doesn't matter if you're fishing in Maine or a great lake.. The pull of a dipsy is the same!!
As far as the Daiwa vs the okuma..
I don't think short term you'd notice a difference, but I do think after a couple seasons of constant use, you'd find the rod built for a dipsy is "probably" going to give you better results!!
Also.. make sure you adjust the ltension pull on the dipsy to where you want it!!! Super easy to adjust .. I've done it on the fly in the boat many times... to stiff and it won't trip and it'll make it tougher to reel in!!