How to change thesis template to from A4 to B5?

Question

I am using a template for my PhD thesis, but I have a problem with margins. The default is a4paper, but I want put it on b5 size.

% Set up the document:
\documentclass[a4paper, 12pt, twoside, openright]{Thesis}  % Use the "Thesis" style, based on the ECS Thesis style by Steve Gunn

I changed "a4paper" by "b5paper" but it doesn't work. I also changed the margins in the .cls file but it doesn't work either. How can I fix this problem?

Thanks in advance!

I am using a thesis template downloaded from shareLatex available at: https://es.sharelatex.com/templates/thesis/easy-thesis

I tried to print the a4paper and printed in as b5, but i have problems with the resolution of the figures. Thus, I prefer change the size direclty in Latex.

Answer 1

Just pass the option to the class:

\documentclass[b5paper]{Thesis} 

But be sure to remove all these lines from Thesis.cls:

\PassOptionsToClass{a4paper}{\baseclass}

\usepackage{vmargin}
\setmarginsrb           { 1.5in}  % left margin
                        { 0.6in}  % top margin
                        { 1.0in}  % right margin
                        { 0.8in}  % bottom margin
                        {  20pt}  % head height
                        {0.25in}  % head sep
                        {   9pt}  % foot height
                        { 0.3in}  % foot sep