Modify color scale legend guide to match line size in ggplot2

Modify color scale legend guide to match line size in ggplot2

How do you override the aes size value for a ggplot2 legend guide based on
a column in the data set?
Refer to this example:
library(data.table)
set.seed(26798)
dt<-rbind(data.table(Trial="A",Value=rweibull(1000,1.0,0.5)),
data.frame(Trial="B",Value=rweibull(100,1.2,0.75)))
# Add a count and something like a cumulative distribution:
dt2<-dt[order(Trial,Value),list(Value,N=.N),by=Trial][,list(Value,N,y=1-cumsum(N)/sum(N)),by=Trial]
dt2
## Trial Value N y
## 1: A 0.0003628745 1000 0.999
## 2: A 0.0013002615 1000 0.998
## 3: A 0.0017002173 1000 0.997
## 4: A 0.0022597343 1000 0.996
## 5: A 0.0026608082 1000 0.995
## ---
##1096: B 1.6821827814 100 0.040
##1097: B 2.2431595707 100 0.030
##1098: B 2.5122479833 100 0.020
##1099: B 2.5519954416 100 0.010
##1100: B 2.6848412995 100 0.000
ggplot(dt2) +
geom_line(aes(x=Value,y=y,group=Trial,color=Trial,size=N)) +
scale_size(range=c(0.1, 2)) +
guides(size=F, color=guide_legend(override.aes=list(size=2)))

I would like the line thickness for each value of Trial in the guide
legend to match the line in the plot (i.e. "A" should be thick and "B"
should be thin). Edit: @Arun gave a good suggestion for adjusting each
thickness manually, but my actual dataset has many factor levels and is
constantly changing, so I need it to be "dynamic".
The answer from @DidzisElferts to a similar question (Control ggplot2
legend look without affecting the plot) shows how to set the size to a
static value. The size=2 part in the last line of the example above lets
me change the line size of the legend, but I would like it to match the
size of the line in the plot. Using size=N instead seems logical, but it
gives the error "object 'N' not found". What is the correct syntax?