It's rather difficult to predict how your hand will react to your particular playing position, but here are a few pointers:
1. If there's a significant angle between your forearm and hand, you're straining your hand.
2. If you pluck hard, you're straining your hand.
3. If you're stretching your fingers to reach the thinner strings, you're straining your hand.
Personally, I find using floating thumb the best way to play, hands down. I just noticed that's how James Jamerson did it, so how could it be bad

?
That and playing a bit softer on average will definitely be easier on your hand and wrist.
Rune