robert e , thanks for suggestion. I will try a higher tension E carbon string and leave the rest normal tension. I can always put some higher tension Savarez carbons all around, the result is always a much cleaner sound, but In this case my musicality will decrease. I am so sure about the fact that lower tension will make Fiesta even worse, because Fiesta's treble volume is already lower then basses . The overall Fiesta sound is rich but also slow, lazy, so less tension will also bring less treble volume and clarity.
Still, guys, I've made my google, looks like there are more people like me who complain about Kremona's tone problems. These guitars are a hit or a miss - no guarantee, no consistency, no reference. For 999$ you can buy a Spanish made award winning Cordoba 45MR, for 500$ there are excellent La Patrie guitars, at 700-999$ price range there are so many options. Think twice before ordering a Kremona online, especially a used one, you might end up buying my guitar and my problems ).