Your "nic salt" solution appears to be empty of nicotine. It's possible the "boosters" you were given were in fact, nicotine salt boosters. Read the bottle, and let us know what they say. Typically with an unflavored "juice" boosters are added to increase nicotine strength. I'm not entirely clear on what strength your "boosters" are and I'm not sure you are, either.
If you are using a N2 tank, your nicotine strength can likely go higher than if you were using a sub0hm device.
AND a NOTE OF CLARITY, LOL, I have said this multiple times on the forum. "Nic salts" are the "new" "what's new, hot and expensive" of vaping. Many manufacturers and vendors will make claims that their devices are "nic salt capable."
ALL devices are nic salt capable, it's just that you have to match the strength (pretty much) to the device you are using. Let's say someone who sub0ohms is using 6 mg/ml of regular freebase nicotine, that person should start using nic salts at the exact same strength, or possibly even slightly lower (though I haven't found a need to reduce my nicotine with nic salts. I use them at 18 percent, and they are pretty much 1:1 equivalent to regular nicotine, with the slight caveat that SOME people may find they absorb more quickly into the body, so it's not a terrible idea to watch out for nicotine overload symptoms on first use. I did not run into any, I use them because I don't PREFER a throat hit, and salts are much smoother.
So, once you figure out how much of your (possibly) salt nic shots to add to get to your usual nic salt level (you can use a juice calculator for that) then mix some of your "flavor" a the right percentage to your "nicotine shot" to reach around what you would normally use, and go right ahead and proceed.
The reason nic salts tend to be marketed to higher nicotine setups is that most sub0hmers are already using lower nicotine and don't find the need for "less" throat hit. If you are targeting higher nicotine, nic salts allow a greater range, sometimes (IMO) a ridiculous range, like the Juul which has a whopping, 50 mg/ml nicotine ratio, make vapeable by nic salts. It's also an incredibly weak delivery system.
But, there is no "magic" to nic salts. They offer some slightly different qualities but can be used in ANY device.... At the correct strength.
Best of luck,
Anna