This sounds like a byzantine workflow, and unnecessary. A TIFF cannot be updated, edited in FCP once you bring it in.
I would take that Excel file and Save As? under a distinct name, in "Text, Tab-Delimited" format.
I would then open FCP, and then open Boris Title Crawl. Open its stage by clicking on "Title Crawl"-- it's a button to the crawl editor.
I would then click the Import File button at the bottom of the stage window, navigate to your saved Excel file and select it.
Tab manipulation in Title Crawl (or 3D): tabs can be precisely adjusted in the ruler atop the stage. The default tab is Flush Left. Click once to place one, or drag it from the corner well.
If you want to center a word or line on a tab, click the "L" tab twice and it changes to an inverted T, for "Center tab".
Click three times to make it a Flush Right tab.
(There may be key commands for these, I haven't found any modifiers to work.)
Space your gutters to suit, and remember, you can also change any text line size or font to taste.
Click Apply when done and drag the clip into the timeline. Stretch or reduce it to fit desired time and if required, render. To edit or tweak, double-click the clip and re-open the stage.
Until the better elements of LiveType are folded into FCP as a live overlay, Boris is the handiest out there.
HTH
- Loren
Today's FCP 4 / 5 keytip:
Set a multi-parameter Motion FX Keyframe with Control K !
The FCP KeyGuide?: your power placemat.
Now available at KeyGuide Central.
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