We keep the stock 80mm blade on our TB's and do not remove any material at the idle and low rpm cruise positions. This is what keeps your computer happy and prevents and check engine lights.
Our 85mm starts at 83mm at the front, then opens up to 85mm just before the blade, then tapers back down to 80mm at theblade, again opens up to 85mm just behind the blade, and then back dowm to 83mm at the back of the TB.
The 87mm starts at 83mm in front, opens up to 87mm just before the blade, tapers back down to 80mm at the blade, then opens up to 85mm behind the blade, and then back down to 83mm where it meets the manifold.
The port shapes are very complicated, but they have shown great results for us for such a simple upgrade to install. Easy hp gains without having to mess with engine codes like we are seeing from the true bore 85mm and 90mm TB's.