Recent work has explored using self-supervised learning(SSL) speech representations such as wav2vec2.0 as the rep-resentation medium in standard two-stage TTS, in place ofconventionally used mel-spectrograms. It is however unclearwhich speech SSL is the better fit for TTS, and whether ornot the performance differs between read and spontaneousTTS, the later of which is arguably more challenging. Thisstudy aims at addressing these questions by testing severalspeech SSLs, including different layers of the same SSL, intwo-stage TTS on both read and spontaneous corpora, whilemaintaining constant TTS model architecture and trainingsettings. Results from listening tests show that the 9th layerof 12-layer wav2vec2.0 (ASR finetuned) outperforms othertested SSLs and mel-spectrogram, in both read and sponta-neous TTS. Our work sheds light on both how speech SSL canreadily improve current TTS systems, and how SSLs comparein the challenging generative task of TTS. Audio examplescan be found at https://www.speech.kth.se/tts-demos/ssr tts