I found that the OEM spring works best in this application. The portion of the spring that sits on the spring rest needs to be heated and bent to achieve the proper amount of tension. It took me 3 springs to get my first one right but the second pole I did was spot on.
If you have a stock spring and a Blowsion spring side by side you can see how much of a difference there is in the angled portion that sits on the spring rest. Stock is not enough tension, Blowsion is too much. Blowsion needs about 15° taken out of the bend and the stocker needs 15° added to it. If you have them both side by side imagine the correct bend to be somewhere in the middle.
Heating the springs is a bit of a trick, too much heat takes out the temper and the spring bends too easily if over tensioned. I used a fine tipped jewelers torch with very focussed heat but I think that quenching the spring after may play more of a part in maintaining spring temper than anything. Metal workers can likely add some better info on that subject.