I found that depends on the ratio of the two masses only.

I tried considerng ##p## (along ##x##):

Before: ##0##

After: ##m_1v_1+m_2v_2##

and together:

##0=m_1v_1+m_2v_2##

so: ##m_1v_1=-m_2v_2##

squaring both and rearranging:

##v_1^2/v_2^2=m_2^2/m_1^2##

Kinetic is ##K=1/2mv^2##

So:

##K_1/K_2=(cancel(1/2)m_1v_1^2)/(cancel(1/2)m_2v_2^2)##

substituting: ##v_1^2/v_2^2=m_2^2/m_1^2##

##K_1/K_2=(cancel(m_1))/(cancel(m_2))*m_2^cancel(2)/m_1^cancel(2)=m_2/m_1##