My 665N 2-speed sits on a 300G OTI - it's a great jigging combo. Handles fish to 35lbs easily (I haven't caught anything larger with it yet). Super light package and handles 20lbs+ of drag (love that maximum drag ). I primarily use it down to 300' of water. In deeper water, I use the 600G OTI with a 665W 2-speed.
the oti 300 has decent power, toneyc used mine on a 100lb black tip in short amount of time. i think the 665 would match up with the 400 and 600 gm better. 270 and 870 on the 300 would be killer combos.
The OTI 400g won't be out till late this Summer I think. If you're lookin to use it soon, I would get the 300g conventional, they are on sale at tackledirect.com for $199.95 right now, free shipping over $200 as well: