(request) )-scale portal dimensions and ideas

[nik_n_dad]

Happy pre-turkey day.

I'm helping build a mountain for a relative's O-scale layout this weekend. Unfortunately, no portals to be had in this particular town.

Does anyone have the inner dimensions for a chooch O-scale single concrete tunnel portal? Does anyone know where we can order (and what the dimensions would be) for a double 0-scale portal?

Thx

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