How do I make my opening reportorie stronger, specifically my Grand Prix Attack against high level competition? I saw the DVD Killer Grand Prix Attack from GM Gawain Jones. This helped a lot. However, I have some trouble with some concepts against 2 ...e6 lines. According to the DVD the second plan of the Grand Prix Attack is to play Bb5 and capture the Nc6 to give Black double c pawns then attack the double pawns in a positional way. However, I sometimes heard you have to transition to Closed Sicilian or Open. Here is an example were I'm unsure. 


e4 c5
Nc3 e6
f4 Nc6
Nf3 d6
Bb5 Nge7 
o-o g6
d3


Would it better to play Bb5 earlier to go for the double pawn plan or 5. Bb5 here is better such as this game was played? Would 7. d4 be better than 7. d3?

What are further resources to study the Grand Prix Attack seriously?
As resource: 

Please check Lawrence Trent's analysis from White's perspective and Andrew Martin's's from Black's perspective.

About line:

I don't find it correct to say anything about this line without studying state-of-the-art. So, you better check experts analyses for suggestions.