No more generic way to rescale canevas ?

Now set size does not change the canevas anymore, how can I rescale my output file without typing set term <foo> size  X, Y for every <foo> terminal I may use to render my graph in the future ?

I understand this has been done for better consistency but I usually use wxt, postscript and png terminals, It is a real pain to calculate H and W for each terminals so it fit the graph.

Thank you,