I used a different approach. The tutorial you're referring to does have the word "gradient lines" in the title but it doesn't mean you really have to use gradients.
I used Create Tiled Clones... option
Here's the result:
And here's how you do it (You don't need to have the latest build for this, 0.45 version will do):
Create some bold text, I colored mine in beige (ish).
Next you want to create horizontal stripes that vary in their thickness and in the amount of space between them like this:

You do it by making the first line yourself (the thin one near the top of the text) using rectangle tool (so youre drawing a wide and thin rectangle) and let Inkscape draw the rest of them; while the rectangle is selected go to Edit > Clone > Create Tiled Clones... and use these settings:
Symmetry:
P1: simple translation
Shift: Only change Shift
Y per
row to 1000% and
Exponent per
row to 1,10
Scale: Only change Scale
Y per
row 340%
At the bottom of the dialog set Rows, columns: 7 x 1
and Use saved size and position of the tile
(you should leave everything else intact)
Hit the Create button
If you don't like what you see you can click on Remove, make some change in the settings and Create again
Once you've got the stripes the right thickness and distance from each other you're ready to mask them into the text shape:
Group all the tiles (stripes) so it's easier to work with them (you may also want to delete the original rectangle that served as the cloning template)
Duplicate the text (the duplicate will appear on top of everything)
Change it's color to White
Convert it to a Path (Path > Object to Path)
Shrink it using Inset (Path > Inset), I applied Inset more than once, it depends on how far away you want the stripes from the edge of the text
Select the group with the stripes and the shrinked white path and make a mask (Object > Mask > Set)
Done!