Double Fianchetto V London...and Slav Type Setups

This seems to do well against the London:

When I see an idea with either white or black I like to see if the idea has any merit with colours reversed. The below game starts as a KIA but converges to a simiiar game with colours reversed. I discovered it through "Explorer" with an initial 1c4 c6 mover order:

This raises an interesting chessophilosphic idea. If an idea with black is good and reasonable as opposed to objectively better should the idea be played with both colours to decrease work by increasing experience of a particular type of position ?

it's possible, and you will probably become very familiar with ideas, however keep in mind that the extra tempo as white does not assure it will be better.

I don't know much about those KI positions, but a classic example is the Dutch defene vs the Bird opening. In the dutch (1.d4 f5) white has already played d4, thus weakening control over the d4 square. In the bird, the extra half tempo actually probably harms white more than helps, because already black can play d6, helping him force through e5.

Yes thanks. You are right about the extra tempo and black's "information lead". For instance in the double fianchetto as white, black seems to do very well when the LSB develops to g4 rather than f5 - although of course with colours reversed the "London Bishop" has already developed to f4 early...

I'd say it's almost always better to favor reasonable moves you understand over objectively best moves you don't really understand.

As for playing the same thing as black and white, the more system-like the opening, the more options your opponent has against it, and the more likely your opponent is the one getting a position they're comfortable with and understand. 

In the example games his opponents happened to play very similarly. 

It's a nice way to develop but the play should depend on the opponent's pawn structure. Either side can capture a pawn somewhere and change the direction of the game.