the floating hand is actually quite relaxed becoz ur fore arm is resting on the guitar. Although, to do this, its better to strap your gee-tar pretty high. Look at Petrucci.
The best method is to incorporate all.
Floating hand gives a versatile perspective as you can move around. If you place ur hand on the bridge, you can train perhaps your muting skills.
Although, putting down your gain to practice is a good thing, as it trains your accuracy and tone control, there IS one down point.
The electric differs from the classical also because of this point....which is the sound control. As you play overdriven sounds/distortion, a player tends to loose control of the instrument. It might seem that u could shred with low gains, but when you up the gain, u might notice alot of humming, mistakes...accidentally hitting other strings..etc
Hence, playing the electric with high gain requires skill in "clinging on to the guitar" which is muting the un-used strings with either your pick hand or fretting hand.