I have had my Triton Refs since July of 2017. I have used the following amps with my speakers:
Odyssey Stratos Extreme.150wpc
Conrad Johnson MF2550. 250wpc
McIntosh MC152. 150wpc
McIntosh MC302. 300wpc. My current amp.
20wpc won’t be nearly enough for the speakers even though you are only driving 2 six inch midranges and the folded ribbon tweeter. The 300wpc amp seems perfect for the T Refs. Personally, a 150wpc amp is the least I would use unless you play the stereo in the 70DB volume range. It makes a BIG difference.