I'd recommend having both lenses - the 135mm and 90mm (or wider)

I have an MPP 4x5" and a DaYi 6x12 holder. When shooting full 4x5" or 9x12 cm, I use the 135mm 90% of times, only occasionally either the 90mm or 270mm that I have (and lately, the 270mm comes more often than 90mm).

On the other hand, when composing for the 6x12cm frame, I use 90mm lens most often and a lot of times I wish I had something wider (I intend on buying either 75mm or 65mm).

But you have to find your own preferred way of seeing, just my 2c...