I don't think it much matters. What does matter is that you practice with your ears and you practice a lot. Play along with something that allows you to identify when your intonation is off. For example, iRealB is an iPad app that allows you to play along with a library of chord progressions or you can program your own. Also, technique is probably even more important on fretless because muscle memory is what is going to ensure good intonation on fast parts. Finally, when you develop enough confidence to play your fretless at rehearsal or a performance, record the results. I use a Zoom H4N to record rehearsals and performances. I listen to the playback, identify problem parts, and then focus on those. Sometimes changing the fingering fixes an intonation problem, but the main things are using your ears and practice, practice, practice. Those seem to be the themes in the responses above. BTW, I have an unlined four string ebony fingerboard from Warmoth and use roundwounds.