There seems to be that sweet spot when on the step of not too nose high and not too nose low.

But I was told that when it is no longer just some little waves but ones that are getting larger(lets say approaching whitecap size or significant bumpiness) that the aircraft should be in a slightly more nose low attitude so the floats will "cut through the waves" on takeoff and landing.

Is that what you typically do?

It's been a while but "sweet spot" still applies but I don't know how you define this. To me, you find it, which becomes muscle memory, on every takeoff adjusting for conditions.

As a foot note, waves with white caps on inland lakes usually indicates that it's too rough. Unless there are sheltered areas and yes, long taxis are probable but why operate in conditions that beat the aircraft and floats to death. I was lazy and hated pumping floats so I avoided rough water and operated in sheltered areas and dealt with the rough water at taxi speeds.

Agreed to all above.
Only thing I’ve got to add is when I couldn’t avoid rougher water that was still within the limits of the airplane, I’d do my best to get the weight into the wings and off the floats as early as possible. If anything, a slightly nose high attitude would allow this while maintaining cautious control so as not to do anything dumb once the plane became airborne. Again, the aircraft will tell you what it needs. We just have to listen.
G

I agree with what's been written. The plane will tell you what will work. There'll be a narrow window of what works, with "doesn't work" on either side. Just don't let the plane get porpoising. But you can pound a plane to death, overheat an engine, and erode a prop in rough water, so think it through before you try. Generally, if you have to ask yourself if it's too rough, it is.

If you run too nose low in the water, you won't create the angle of attack needed to get airborne at a slower speed. And you'll have more hull drag, to slow your acceleration. If the bows are too low, the more forward buoyancy point leaves you a bit more vulnerable to a waterloop if there's a crosswind, and you can't hold it. More a risk with flying boats than floatplanes, but worth considering. On a wheel plane, the designer controls the fuselage station where the weight of the plane is supported during takeoff, in a seaplane, you do! Get it too far ahead of the C of G, and you've created a taildragger, so control yaw carefully!