Garrett turbo V band flange dimensions

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Quick background, I have been running a GT2860RS on my RB20DET for years and for my purposes I have been happy with it, but the time came to replace it and I have gone with a GTX2860R Gen2 to hopefully get what amounts to just a bit more of the same with the better compressor, I was basically just about at the choke line in places. I tracked down a T3 flanged internal gate housing for it as I was sick of the crappy T3 to T25 adapter I had on it. The two part designs are just rubbish.

The opportunity knocks to change to a tubular manifold and external gate (I have not even started it up with the new turbo on it yet) and I want to keep it relatively future proof as whenever the 20 breaks or wears out (Been waiting ten years) I would fit a 25, or build a 30 based engine as I have a good 30E block in the shed. I am looking at manifolds, with 6Boost being just one of course but one that is generally known to fit. The issue is deciding on what flange to run. At the cost of a much dearer turbine housing I could whack the TiAL housing that suits this turbo on as they  run the same V band flange for the GT28/30/35 housings, but when I change to a bigger turbo I am up for another expensive housing. The Garret V band is a cheaper housing but the flanges are different between GT28 and GT30/35, meaning if I fit one of them I am possibly down for a new flange being fitted to the manifold later.

The question for the gurus is. Does anyone have a definitive drawing that shows the GT28 and GT30 B band flange inside diameters? I have not had any luck so far googling for drawings. If it is not too different so that I could not make a quite short adapter while having a decent taper on the ID, I could get a manifold with the GT30 flange on it and have a GT30 to GT28 V band adapter spun up, meaning two V band clamps but later when a bigger turbo is required I just remove and bin the adapter.

TL; DR, anyone got proper drawings or measurements of a Garrett GT30 versus GT28 turbine inlet V band flange?

[KiwiRS4T]

https://www.google.co.nz/search?tbm=isch&q=garratt+V+flange+dimensions&chips=q:garratt+v+flange+dimensions,online_chips:v+band&usg=AI4_-kTdQEC2ysQ5R7vP-AFb0KImIDnaEg&sa=X&ved=0ahUKEwjApsLV_6vhAhUJeH0KHWPcDt0Q4lYIMCgH&biw=1920&bih=966&dpr=1

[Blue]

I was hoping there for a minute, but copy pasting that result gets me much the same as I have been getting, loads of pictures, no actual dimensions, at least not of the V band housings, not the ones I am looking for anyway. Time for some emails to suppliers like GCG I think.

[Blue]

Managed to track down some info via GCG, not looking great for the GT30 to GT28 adapter idea, it would have to be impractically long to have a taper I could accept. The sides would have to converge at nearly 30 degrees (The two sides together)  to put the turbo in an acceptable location.

I was hoping not to spend the money but a TiAL housing and flange might be the go, single size between GT28 and GT30/35 for future use.