Here's the final script I used. I've reformatted and added comments to make it easier to read.

# Crop and upsize using anti-aliasing
# Use less aggressive settings for the probe droid
# interrogation scene to avoid artefacts

a=mpeg2source("e:\project.d2v").crop(0,102,0,-104).eedi2().trim(0,58642)
b=mpeg2source("e:\project.d2v").crop(0,102,0,-104).eedi2(maxd=15,nt=8).trim(58643,-351)
c=mpeg2source("e:\project.d2v").crop(0,102,0,-104).eedi2().trim(58994,0)
source=a+b+c

# Adjust the luma (Y) levels
# with a little function I found at Doom9. A modification of Didée's YLevels,
# this one gives a lower brightness and increased contrast
# without excessive "crunching" or "clipping"

source.FlimsYLevels(10)

# Subtle grain filtering for hot pixel removal

DeGrainMedian(limitY=5,limitUV=5,mode=3)

# Adjust colour, more saturation, less pink

tweak(sat=1.15, hue=-6.25)

# Sharpen and resize to NTSC DVD resolution

limitedsharpenfaster(dest_x=720, dest_y=366)
addborders(0,57,0,57)

# Add subtitles for Greedo scene
# Approximate match for theatrical font and position,
# compressed horizontally to keep text within overscan "safe area"
# Note you need AviSynth 2.58 Alpha for the font_width parameter

subtitle ("Going somewhere, Solo?", \
-1,370,70663,70698, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("It’s too late. You should have paid him when you had the chance.", \
-1,370,70825,70931, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("Jabba’s put a price on your head so large every\n" + \
"bounty hunter in the galaxy will be looking for you...", \
85,330,70940,71088, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5,lsp=1)
subtitle ("I’m lucky I found you first.", \
-1,370,71098,71137, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("If you give it to me, I might forget I found you.", \
-1,370,71203,71282, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("Jabba’s through with you.", \
-1,370,71365,71406, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("He has no time for smugglers...", \
-1,370,71435,71489, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("...who drop their shipments at the first sign of an Imperial cruiser.", \
-1,370,71498,71595, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("You can tell that to Jabba. He may only take your ship.", \
-1,370,71656,71748, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("That’s the idea.", \
-1,370,71806,71833, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)
subtitle ("I’ve been looking forward to this for a long time.", \
-1,370,71843,71931, \
"Franklin Gothic Demi Cond",36,$ffffff,font_width=10.5)

function FlimsYlevels(clip clp, float amp)
{ wicked="x x 16 - 34,85493 / sin "+string(amp)+" * -"
return( clp.mt_lut(Yexpr = wicked) )
}