variable brick wall

Hello, I am trying to add an extra parameter to the attached definition.. could anyone help?

The attached definition generates a system of one size brick on any surface but I would like to start with one length size brick and gradually finish with another (e.g. from 50cm to 80cm length). I understand it needs a gradient attractor to modify the length parameter but i cannot figure out how to link it with the resulting grid of divided points

I would also like to be able to modify the gap in between. Any ideas?

Thank you in advance