thanks i forget how far back if this was answered

You can convert a number of Characteristic dice into Stance dice based on your position on the Stance meter. So how many Reckless or Conservative pieces you have on your track, where you are on the track, and what your baseline Characteristic is all determine how many Stance dice you may have on a given roll. For example, assume you have a Stance meter built with 3 Reckless and 1 Conservative pieces. When an encounter starts, you are normally in neutral stance. You get one free shift on your Stance meter for free each turn and additional shifts can be taken at the cost of 1 Stress per shift. So assuming you shift one space into a Reckless stance on your first turn and don't take any Stress to move it further, you can convert only 1 of your Characteristic dice to a Reckless die. If the Characteristic you were using is a 3, you would roll 1 red Reckless and 2 blue Characteristic dice. If you move deeper into your stance on subsequent turns or by taking Stress, you can convert more Characteristic dice into Reckless dice, up to either the max of your stance meter or your Characteristic value, whichever is less. So if you had a Characteristic of 4, you could at best roll 3 Reckless dice and 1 Characteristic dice. You wouldn't be able to convert the 4th Characteristic die into a Reckless die unless you spent the advancement (assuming it is available) to purchase another Reckless stance piece. On the other hand, if your Characteristic is a 2, then you don't derive any benefit from being 3 deep into a Reckless stance, since you are only going to get to roll 2 Reckless dice (and 0 Characteristic dice). Also note that in this example, if you shifted into a Conservative stance, you would only ever be able to roll 1 Conservative die regardless of what your Characteristic value is since the stance meter only has one Conservative space.

Fast and easy answer: You can't convert more dice than you have. So, the upper limit for conversion is always going to be your base stat value.

Whether your stance track allows you to even come close is another issue entirely. ;-)

Both the above answers are true.

- You obviously can't covert more dice than you have characteristic dice.

- You can only convert as many dice as your position on your stance track.

Thus, for example, if you had...

1) a Characteristic of 8

2) had purchased stance pieces to have 8 Reckless

3) had attained the 8th (end) space towards Reckless

You could conceivably use 8 Reckless dice on a task. Keep in mind #3, though. There is a time and/or Stress limitation to getting to max conservative/reckless stance. In my experience, fights and encounters don't normally last too long, so you'd need to gain a bunch of stress to shift your stance fast enough to use a large 'max' (probably for anything above 4, in fact).

You can actually get a benefit for being further in a stance than you have points in that characteristic, but that's only if you use an action that has an effect based on how far you are into a stance.

So, while you wouldn't be able to roll 4 reckless dice on a roll with a characteristic of 3, if the action you took gave you a bonus based on being a certain distance into the reckless stance, it would be worth it to be that far into the stance.

I've only had a fairly quick look at the Adventurer's Toolkit, but IIRC, some of the cards in there do things like adding a bonus to damage for the number of steps into the stance you're in if you get enough successes or boons.