RooFit: LEGO plot and total ChiSquare value

Dear RooFiters,
I need to ask you abou two things…
I have a 2-dimension histogram and I fitted it using two pdfs(with the RooProdPDF class).
First, I need to know if there is any way to have the total chi-square value?
Also, I only managed to plot the projections of x and y axis, but I wonder If I can have a 2d plot?
As I plot the projections, I retrieve the chiSquare from each frame but I think it would be better If I could have the total chiSquare…

Thank you in advance!