I've been thinking on how to handle task / conflict resolutions and have come up with the following;

1) Characters encounter an obstacle (Bob is walking along a mountain path when he comes across a fallen tree in the path)

2) The character decides what he wants to do and what attributes he wants to use for it (Bob decides to try and squeeze through it, using dexterity & analysis, he has dexterity 11 and analysis 7)

3) The GM decides on a target number, he doesn't tell the character it but does describe it in a way that might give it a hint (The gm decides on TN of 20, he describes the obstacle as 'The tree looks large and old, it must have been standing on the ridge above you for decades before fallen into the gap, it's branches sticking out like a thousand spears')

4) The player first adds the stats together which he can use as a default without it costing him anything or spend points to boost the score up, he then decides which pool to spend it on between the groups the stats are from, he then spends as many points from that pool as he wants, if any special circumstances or traits / tools are applicable they're added here (Bob's default score would be 11 + 7 = 18, however from the GM's description he doesn't think that is enough, he decides to save his pentacle points incase he ends up in a fight later so decides to spend points from swords, he decides to spend 5 sword points on it, 18+5=23)

5) The GM revels if the character succeeds or not and what degree of success, and how much it fatigues the character (different degrees of success/failure gives different amounts of fatigue, a major success might not give him any fatigue) (Bob's 23 beats the target of 20, however it's just a normal success, the GM then describes Bob getting through and gives him 3 fatigue points for it,)

Does anybody see any problems with this or have any suggestions? I haven't really touched on it here, but besides that there's plenty of different things that can add bonuses or penalties, like traits, tools, or other special circumstances (in the above example Bob would get a bonus for being acrobatic (a trait), and having an axe (a tool) but would have a penalty for being chased by a mob (special circumstance), though ultimately it's up to the GM as the player never learns what the target number is)

I think it's a good system.

Do you always choose only two attributes? Also, could you potentially choose different attributes for squeezing past other than Dexterity and Analysis? How would you justify this within the rules, or is it all up to the GM?

It's up to the player to choose the attributes (maybe have the player choose one, the GM the other) and could be any attributes so long as they can justify it, though certain attrbute combinations might give bonuses / penalties in certain circumstances (so basically it's up to the GM), I'm thinking about letting you choose one attribute twice (which basically just doubles that attribute). Currently I'm thinking that most of the time you just choose two attributes but in certain circumstances you can choose three, finally I'm thinking maybe if you have someone helping you out you add one of their attributes to your two but they can't spend any points for the task.

That sounds complex, but if you had rigid rules as to when each circumstance (doubling, selection, using three, justification) can be used. Otherwise, very sound. I like the idea of having the GM pick one and the player pick the other. The GM could pick the one that "makes sense," and the player can be as loony as he likes but has to interpret why he chose a particular attribute for something.

777,
  Have you looked at ...In Spaaace! ?
http://www.gregstolze.com/inSpaaace.zip
  The mechanics are diceless like yours. And you get a consolation prize if you lose. Also, the optimal play strategy delivers a great story arc where the PCs lose repeatedly but triumph in the end. I really would recommend it for something like this.

  If not that, then some kind of luck/Ass Saving Points so that players can make the contests that matter to them. Even if they guess difficulty number wrong...

I plan to include a mechanic I'm currently calling plot cupons that allow the player to influence the plot, get new powers as the plot demands it, etc, and so on.