The playtest group I normally test TSSSF with visibly reacted negatively when they saw the playtest sheet (one of them physically recoiled) and more or less asked to stop the game after three turns. After a few turns, we had learned enough to give plenty of feedback on the sheet.
According to your original post, the main points of this sheet are: 1. To see how often Goals are won and 2. How hard they were to achieve to determine game "flow". Based on this and general playtesting experience, we produced the following notes:
-Numbers without context isn't that useful. Things like number of Goals is nice, but knowing which Goals are active, were achieved, etc. is much more useful. Names are generally more important than numbers.
-Notes should be taken after the game (Usually. Hotfixes for the sake of testing is fine). The information, concerns, etc. that stick with players at the end of the game is the most relevant.
-Taking information down during the game slows it down, players don't have fun, and in extreme cases forget what is going on in the game. Taking down information during a turn took twice as long as it took a player to perform a full turn. Since end of turn information had to be recorded as part of this sheet, gameplay was stopped every turn so that the information recorder could catch up.
-TL;DR: The best way to test is to play a lot. See what works and what doesn't. Notes will come naturally from playtesting. Most versions of games I test for work are ideally tested hundreds of times each version if possible. Obviously this isn't possible for everyone, but I'd imagine you've played enough TSSSF to have some good intuition on set testing and game flow.
This is not to say that a playtest sheet is irrelevant, just not to this extent. To help, our group broke down each element on the playtest sheet and noted why we felt it was relevant or irrelevant to general testing:
Build: Relevant. Obvious reasons.
House Rules: Relevant. Obvious reasons.
Date: Irrelevant unless one is compiling data from multiple versions or possibly over long periods.
Number: For active playtesting, number is irrelevant. If one is playing so much that it affects gameplay they probably shouldn't be playing as this affects good playtesting.
Initial Goals: Point value isn't relevant, but what Goals are active are. You can glean point value from the names and what Goal requirements are is much more relevant to game flow than the point value.
Hand: Irrelevant. This is almost always 4 Ponies and 3 Ships (in my experience at least).
Draw: Somewhat useful but time consuming to track, especially with Pinkie Pie powers. Just some general information on how often digging for many cards to achieve certain Goals is useful and how often this occurs.
Search: Same as Draw, but with digging for answers.
End: This info can be gleaned from other sheet information. Not particularly relevant.
Used: Same as End, but slightly more relevant. What cards were used is much more relevant than the number of cards used. Somewhat like Draw and Search in that many cards used can be interpreted as using powers to achieve Goals, though without knowing which cards were used it's hard to say.
Grid: Irrelevant unless board wipes occur. What cards are on grid are somewhat relevant (like static powers), but not so much number.
Discard: Irrelevant. Information can be gleaned from other data.
Won: As stated earlier, which Goals are won is much more useful information than number of Goals won, though number can still be relevant.
Replaced: Irrelevant. Hardly any Goals refer to this and without knowing board state it's hard to say if they were used to get rid of hand, deal with threats, or deny player's possible power usage.
Duds: Irrelevant. In my experience, this hardly ever happens.
Notes: Extremely relevant for reasons stated above.
Score: Relevant. Obvious reasons.
Goals: Overarching information like this can be relevant, especially as it can be recorded after the game is over. Most relevant is Goals achieved, followed by discarded, then active.
Pony: Same as Goals.
Ship: Same as Pony.
I hope this information will be useful to your research. Please let me know if you'd like any clarification on anything or if you have a newer sheet you'd like my group and I to test out!
Playtest sheet:
http://i.imgur.com/lDKZUjG.jpg (Rodeo was the only achieved Goal):