Here is a post I made on a thread on the 2NT GF balanced response to 1H/S.

Playing 2NT as GF balanced is certainly an improvement over normal 2/1 GF methods. However there is not enough bidding space for opener to properly unwind unbalanced hands and big hands over the 2NT response. That said, most hands will have no problems in getting to the best spot.

I believe it is better to play the 2C response to 1H/1S as either GF balanced or GF Cs. There are various structures possible after this, some involving complex relays. If one is aiming for simplicity combined with effectiveness, one could try:

After 1H/1S- 2C;-? (note M=opener's major)

2D: fewer than 4 in other major, not 6+ in M with extras. After 2D:
---2H: GF with Cs.
---2S: GF with 3+ in M and Cs.
---2NT: GF balanced.
--- 3X: GF with Cs and very distributional.

2H: 4 or longer in other major, not 6+ in M with extras. After 2H:
---2S: GF with Cs.
---2NT: GF balanced.
--- 3X: GF with Cs and very distributional.

2S: 6 or longer in M, extras.
---2NT: GF balanced.
--- 3X: GF with Cs.

The concept is to use 2C as a steppingstone on the way to bidding 2NT with GF balanced, to give opener more bidding space to unwind hands.