Spear Dancing Style and Magic Weapon/Dual-Balanced Weapon

Question

The Spear Dancing Style allows, when using the style, to grant the double special weapon feature to a spear or polearm from the weapon fighter group.

I have two questions about the consequences of this weapon feature change:

First, how is it managed for a magic weapon ? If a character uses a spear +1, will the fact of giving the magic weapon the double feature allow to use both parts as a weapon +1 ?

Next, based on the same ambiguous state, there is the question if a spear with the Dual-Balanced Weapon Modification is used.

When a character uses this style, are both weapons supposed to benefit from the modification? Would it need to apply the modification twice on the spear, despite the fact it is not a double weapon when the weapon is being upgraded, or would just one part benefit from this weapon modification ?

Answer 1

The feat Spear Dancing Style says

While using this style, you grant the chosen weapon the double special weapon feature, using the weapon’s normal statistics for its main-hand end and the statistics of a light mace for its off-hand end.

(Emphasis mine.) This GM would rule that the spear's off-hand end remains a spear—and specifically still that spear that the wielder's using, even if that spear's a magic spear—, despite that spear's off-hand end possessing the statistics of a light mace. So in this GM's campaign, a warrior that possesses the feat could buy a lone +5 flaming shock spear and reap the benefits of that +5 flaming shock spear both when the warrior pokes a dude with it and when the warrior smacks a dude with it. (To be clear, that warrior's off-hand attack with that spear would use the statistics of a +5 flaming shock light mace.)

The warrior has expended valuable resources on what's widely considered a subpar fighting style with a simple weapon. This GM would view the warrior as having earned the right not to have to, for example, make magical separately that spear's off-hand virtual light mace!

The weapon modification dual balanced applies only "[w]hen wielding two weapons." Although the warrior that possesses the feat Spear Dancing Style is using the spear as a double weapon (there's no good direct link—search this page for double weapons), the warrior still wields just one spear, so there's no benefit to the warrior in that situation for the spear having the weapon modification dual balanced. The warrior must use two different, separate weapons to benefit from a weapon with weapon modification dual balanced.

Answer 2

Neither of these benefits apply to Spear Dancing Style.

Double weapons must be crafted magically on both ends. In the case of Spear Dancing Style, you would have to "convince" a merchant or ally to work on the butt end of your spear, explaining what you intend to do with it. RAW, you wouldn't even be able to do this because the butt of your spear "isn't a weapon" when you're not in Spear Dancing Style... but you'd be hard-pressed to find a GM that wouldn't allow that reasonable concession; however, one Feat doubling special weapon abilities is not.

Similarly, you don't meet the requirements of Dual Balanced of wielding two weapons. No part of the Modification allows it to be used with existing Double weapons, so Spear Dancing Style is no different.*

*As a GM, I would allow you to use Dual Balanced if you purchased it twice for a Double weapon. This is in line with the Ioun Stone that provides +1 to hit and similar to other options.