there is a good reason they make them in lots of different sizes.....
use whatever you got for an "emergency" repair, but for an electronic installation, please acquire the proper size......
Now, my take on "cheating" on the size......
If you ever have an insurance claim, the insurance company is looking for any reason to deny liability. Lets say you had an electrical fire. Is the fog lifting?
anyway, yes, solder and shrink wrap (or painted tape) will work too!