Some time ago I made attempt to make an UNUN / EFHW (End Fed Half Wave) trafo for 14 MHz, it was a complete failure… I do not know if the cheap toroid ordered from eBay was a fake (T106-2) but nothing worked (high SWR).
Then I ordered the Sotabeams Pico Tuner (at a very good price). It took me about 3 hours to solder the tuner and cut, test an antenna for 14 MHz (20 meter band). The SWR was very good with the antenna at almost ground level.
The first test with FT8 digital mode and my FT-817ND was good. The next day I mounted the antenna on the roof with one fixed end of the antenna in one of the few low trees I have at my garden. The SWR was now a little bit different (higher) but bandwidth was larger.
I noticed a large improvement in both RX and TX when putting the antenna higher up. In just one hour my TX was heard by 51 receivers on FT8 with 2.5 watts from my FT-817ND.
Summary: I can highly recommend the Sotabeams Pico Tuner if you need a simple QRP tuner thats actually works. Also FT8 is a great digital mode for testing antennas and fast QSOs.