I've researched this to death when I had 5g of var powder, but I gave up since I didn't have the skills to turn it into a stable injectable.
The injectable being ~30% more potent is true for winny depot only. Winny crystalizes at the injection site and therefore stays in the body longer (That's why we only inject winny once a day)
Injectable var would theoretically have fat burning properties at the injection site...If it's from the company I think it's from, I would definetely try the injectable.