Plots Ticks Axis Override

I am using the Plots library and I create plots as attached to this post.
The y-ticks label for instance of the plot of “x4” are not nice and I would like to find an automatic way to arrange them (I created this plots inside a script so I can’t manually change every figures).

Here is what I’ve done so far for instance for the x4 plot:

ff=x4
plot(tt,ff,ylabel=L"x_4",label="",xticks=[],xformatter=x->string(Int(x/1e10),"*pow10"),lw=1.7)
px4=vline!(ti0,label="",xticks=[],color=:red,linestyle=:dash)

and here is my layout:

ly = @layout [ [aa;bb;cc;dd;ee] [ff;gg;hh;ii;jj] kk{0.3w}
I would not like to change the font of the ticks.

Any suggestions ?

playout