  Let F be an algebraically closed field of positive characteristic p. The
third author and Will Turner gave an explicit description of the extension
algebra of Weyl modules for GL_2(F). This, in particular, produced an explicit
basis. We examine this basis and use it to give upper and lower bounds for the
growth behaviour of the dimensions of Ext-groups. Moreover, we implement an
algorithm to determine the dimension of any given Ext-group.
