CAI for AU VCT Fairlane

[CONGO MILLENNIUM]

I consider 8.5 L/100 klm on a country cruise in my Fairlane VCT6 is good for a large heavy car.
I'm hoping that modding the CAI could improve the economy and throttle response. A horse power increase is secondary over economy for me as the Tickford VCT 6 is spirited enough for me.
From what i have read the way to keep it looking factory which is the way i want it to look is--

1, Replace the standard snorkel with a larger mouth unit. There are some for sale on ebay. My preference would be a Tickford snorkel having a Tickford motor but they don't come up for sale very often.
Question: are all the large FORD,TICKFORD snorkels to suit AU models the same size or is there a large then an extra large size? I'm not sure of the size in mm's.

2, Replace the induction tube and flexible pipe with one from a BA Barra 6 as the induction pipe from the throttle body has a more constant curve and larger diameter giving an improved air flow.
Also the ventilation pipe from the back of the rocker cover has to be lengthened or replaced and connected to the new BA connection point.
Question: what size is the diameter of the rubber vent pipe?

3, modify the outlet hole of the air box lid to receive a 75mm pipe to allow connection of the flexible pipe.

4, install a high flow air filter.

5, Question: I read where someone drilled a hole(s) through the bottom of the air box and metal panel directly under, I think it was 70mm holes?
Any info on hole location and bennifit if any?
One more thing turbo lower induction snorkels could also be used but i think only in BA/BF air boxes.

So if anyone has done these mods or any advise, different methods etc.
Plenty of pictures would be very helpful.
Cheers