\begin{table}%t3
\caption{Comparison of the different prescriptions used to reconstruct the observed double white dwarfs. 
The symbols $+$, $\sim$ and $-$ mean that the model solutions are in good, moderate or bad agreement with the observations.
The first of the two symbols in each column is based on the mass ratio only and the second includes the age difference.
The method for obtaining the first symbol in each entry is described in Sect.~\ref{sec:multiple_prescriptions}, that for the 
second symbol in Sect.~\ref{sec:age_difference}.
The symbols in the headers of the columns labelled 1--6 are explained in the main text.
The columns for $\gamma_{\rm a}\gamma_{\rm d}$ and~$\gamma_{\rm d}\gamma_{\rm d}$ were left out because they do 
not contain any solutions.  The last two columns show the optimum result and the prescriptions that give this result~(1$-$6).
For the different prescriptions we demanded that $1.46\!<\!\gamma_{\rm s}\!<\!1.79$, $0.90\!<\!\gamma_{\rm a}\!<\!1.10$, 
$0.90\!<\!\gamma_{\rm d}\!<\!1.10$ and $0.80\!<\!\alpha_{\rm ce}\!<\!1.20$.
\label{tab:comp_prescriptions}  }
\small%\centering
\par
\begin{tabular}{lllllllll}
\hline \hline                                                                                             System	& 1: $\gamma_{\rm s}\alpha_{\rm ce}$ 	& 2: $\gamma_{\rm s}\gamma_{\rm s}$	& 3: $\gamma_{\rm a}\alpha_{\rm ce}$	& 4: $\gamma_{\rm a}\gamma_{\rm a}$  & 5: $\gamma_{\rm d}\alpha_{\rm ce}$ 		& 6: $\gamma_{\rm d}\gamma_{\rm a}$		& Opt. res.		& Best prescr.  	\\	
\hline
 0135     & $-/-$          & $+/$$\sim$     & $+/$$\sim$     & $-/-$          & $+/$$\sim$     & $+/$$\sim$     & $+/$$\sim$	  & 2,3,5,6 \\
 0136     & $+/+$          & $+/+$          & $+/$$\sim$     & $+/$$\sim$     & $+/+$          & $+/+$          & $+/+$      	  & 1,2,5,6 \\
 0957     & $+/+$          & $+/+$          & $-/-$          & $+/-$          & $+/+$          & $+/+$          & $+/+$      	  & 1,2,5,6 \\
 1101     & $+/$$\sim$     & $+/-$          & $+/-$          & $-/-$          & $+/$$\sim$     & $+/$$\sim$     & $+/$$\sim$	  & 1,5,6 \\
 1115     & $+/$$\sim$     & $+/+$          & $+/$$\sim$     & $+/$$\sim$     & $+/+$          & $+/+$          & $+/+$      	  & 2,5,6 \\
\multicolumn{9}{c}{}\\					 1204     & $-/-$          & $+/-$          & $+/-$          & $+/-$          & $+/-$          & $+/+$          & $+/+$      	  & 6 \\
 1349     & $+/+$          & $+/+$          & $+/+$          & $+/+$          & $+/+$          & $+/+$          & $+/+$      	  & 1,2,3,4,5,6 \\
 1414     & $-/-$          & $+/+$          & $-/-$          & $+/+$          & $-/-$          & $+/+$          & $+/+$      	  & 2,4,6 \\
 1704a    & $+/-$          & $+/-$          & $-/-$          & $-/-$          & $-/-$          & $-/-$          & $+/-$      	  & 1,2 \\
 1704b    & $+/-$          & $+/-$          & $-/-$          & $+/-$          & $+/-$          & $+/-$          & $+/-$      	  & 1,2,4,5,6 \\
 2209     & $+/+$          & $+/+$          & $-/-$          & $-/-$          & $+/$$\sim$     & $+/+$          & $+/+$      	  & 1,2,6 \\
\hline
\end{tabular}
\end{table}