Where to find heat shrink with solder (solder seal connectors) for wires lighter than AWG 26?

The smallest variety (white) in these things are intended to connect wires between AWG 24 and AWG 26.

Sometimes, I need to connect wires from AWG 28 to AWG 32. Is there a smaller solder seal connector on the market?

Any recommendations are welcome!

Make a Western Union splice and cover it with adhesive heatshrink.

I recall we used rubber grommet hose for strain relief on twisted solid AWG 30. But my guess you could use liquid rubber or nail polish , Brushed on, then wax string tie wraps. Strain relief is essential.