When I purchased my Kamaka HF-2 Concert uke, I had the seller set it up with Martin M600 strings (for a lighter, easier action) which I really love. This required adjusting the nut to accommodate the thinner strings (the original strings were thicker). This is important to know when swapping strings out. Your uke was initially set-up for strings of a certain diameter (be they Aquila, Fremont, D’Addario, Martin, etc.). If you replace thicker strings with thinner ones (and you don’t adjust the nut) you may get buzzing. The reverse, and you may get bad tonality from the strings because the string may not be sitting in the grove of the nut properly.
I’ve also used Worth Brown Medium and Living Water strings on my Kamaka and I’m going to eventually try Uke Logic strings as well. All of these strings are close in diameter to each other to the Martin strings I mention above. Of the three string sets I have tried so far, I prefer the Worth Brown Mediums the best. They have a warmer sound (to my ears) and they feel good when playing.
Hope that helps.
Paul