calculate textsize for fixed width

Where it is quite esay to do in nodebox 3 I have difficulties making the same behavior work in Nodebox 1:
I want text blocks to have different font sizes, so that they align vertically. See the attached photo. My current code does it quite good bot not perfect, it depends on the text input. Does anyone know a better attempt to do this?

txt="Hello Width!"
desired_width=300
fontsize(100)
w_draft=textwidth(txt)
fz=100*desired_width/w_draft
fontsize(fz)
print textwidth(txt)
text(txt, 100, 100)

see: http://nodebox.net/code/index.php/Reference

There is no specific command for that, as I want to scale the text to full width, not make a textarea

Take another look.

Thanks for your help, or let's say clues (^^^)
I was able to do it with BezierPath, file size is the only downside :)

´´´
width=500
last_y=0
for txt in ['Hi', 'Hello', 'Width!']:
path = textpath(txt,0,0)
path.fit(0, last_y, width)
last_y = last_y + path.bounds.size.height
drawpath(path)
´´´

width=500
last_y=0
for txt in ['Hi', 'Hello', 'Width!']:
  path = textpath(txt,0,0)
  path.fit(0, last_y, width)
  last_y = last_y + path.bounds.size.height
  drawpath(path)

Indeed, The "fit" approach is also how NodeBox 3 does it.

I've also tried your approach, and it seems to work fine, only the commas and question marks at the end throw things off. Here's my version and the result:

lines = """Lorem ipsum
dolor sit amet
consectetur adipiscing elit
Donec velit arcu
cursus eu vestibulum id
finibus nec mauris"""

y = 100
line_height = 0.95
desired_width=300
for line in lines.split('\n'):
    fontsize(100)
    w_draft = textwidth(line)
    scaled_font_size = 100 * desired_width / w_draft
    fontsize(scaled_font_size)
    text(line, 100, y + scaled_font_size * line_height)    
    y += scaled_font_size * line_height