Multpile (45x8) graphs of the same page / device: titles crammed

x <- seq(0, 10)

pdf(width=8, height=20)
par(mfrow=c(45, 8), mai=c(0,0.1,0.1,0))

sapply(1:(45*8), function(ii) {
	plot(x, rnorm(x))
	title(paste("test", ii), cex.main=0.5)
	}) -> b.quiet
dev.off()

Dear R users,

I'm trying to plot 45x8 graphs on the same pdf / device for the sake
of visual comparison.
par(mfcol=c(45,8))
par(mai=c(0,0,0,0))

In ?title, I can see there are cex and font settings: I set cex = 0.01
and font = 1: it is still very large, and then I tried setting font <
1, e.g. font = 0.5, Then I get an error:

Error in title(paste(Ppercent, "% ", "t30v2msa1.data", sep=""), cex  
= 0.1, :
     invalid value specified for graphical parameter "font"

Is there a work around so that I can see all the title?
At the moment, if I set the title to font=1, the upper halves of the
fonts / letters of all the title will be cut, so I can't see the
"Ppercent"...

Thanks!

Regards,

     John