You are right, using AddStripOnPlaneY you can add infinitely long strips on the plane, either along x or along z, while AddPixelOnPlaneY allows you to add a “pad” with finite dimensions in both x and z.
At the moment, you cannot change the angle, but that shouldn’t be too complicated to implement. I’ll put it on my to do list…
Note that both strips and pixels are only used for calculating weighting potentials and fields, but have no influence on the “drift” electric field in the chamber.