flow nets are typically derived in Cartesian coordinates. You are really working in radial coordinates. I'd just fire up Modflow, but that's not cheap and requires some context on how to drive the software.

Well equations will certainly give you a basis to evaluate yield, drawdown, area of influence, etc. I don't know the end-game for the OP. Clearly, we know the direction of flow. I guess if you know the shape of the drawdown curve, you'd know the stabilized position of the phreatic surface. From that, you could derive gradient.

I refer you to the following link to the USACE document, "Dewatering and Groundwater Control." There you will find equations for yield and drawdown for flow to wells for artesian and gravity conditions. Also for fully and partially penetrating wells. Find your boundary condition and use the equation accordingly. Base the value, "R" on the grain-size correlation to permeability.

http://armypubs.army.mil/mwg-internal/de5fs23hu73d...,

You will obtain yield and drawdown once you know the distance to zero drawdown.

f-d

ípapß gordo ainÆt no madre flaca!

Plaxis 2D has both plane strain and axi-symmetric (i.e. perfectly symmetric about vertical axis) elements.
Expensive.