Convert 4-string Ukulele bass to 2-strings ??

The typical stretchy strings on a uBass are under such low tension that removing the E and G strings isn't going to hurt the instrument, especially because you're removing the strings symmetrically. If you were removing them asymmetrically, like for example removing the E and A or removing the D and G, you might over time induce a warp into the neck. But again the tension is so low anyway that it's probably not going to cause trouble.

That said, by removing strings you are severely limiting what you can do and/or learn to do with the instrument.

That's your call though.

BTW, another option is to get heavier gauge strings. A number of sources are making higher tension wound strings for uBass now, and those are more like conventional (nylon) guitar strings. They have a sound of otheir own, but if stretchy strings are bothering you, these higher tension wound strings might be more to your liking.

 

When you're playing silicone and similar strings, you get a lot of drag on your fingers and consequent finger noise. To alleviate that, try using some baby powder on your fingers. I prefer a clay-based formula (Burt's Bees); talc is more abrasive, which bothers me.

 

I can't comment on the engineering, but I'll be interested to hear about a metal string that can produce useful pitch in the bass range on such a short scale.

 

Gallistrings makes a flatwound (synthetic gut wrapped in steel) set for these basses that I think is the best string going. Less string noise, feels less like a toy, better sound on all the strings. YMMV, but I would suggest that as an alternative to just removing the offending strings.
Kala Flatwound 4-String Set by Gallistrings - Kala Brand Music Co.

 

Am I the only one that likes the big fat rubbery strings? Lol... Those flats look cool tho. I owned a Kala fretted, and imho fretless is the way to go on a ubass. They just seem to play easier and that Kala loved to fret buzz. I've got a cheap Hadean feetless now. Not much different than the Kala for a lot less.

 

I like them. I don't have Aquila strings though, I've got the Road Toad Pahoehoe.

For me too, the big difference is getting a fretless uBass. The only way to go.

 

Instead of removing strings, I would have tuned all four up a step and tried that. The instrument can stand a little more tension.

 

I tried a Kala in a music store once and found it very cool. I didn't notice any finger noise at all. What are you plugged into? Could be an impedance issue or such.

 

Former geologist here, clay is much more abrasive than talc. Talc may have bigger particles which can feel more abrasive. Corn starch may work too but I would clean the strings frequently if using it.