I believe strongly the Kaikoen get's close to impossible to perform, when at the same Time - the Supersayan State is activated. I saw Goku only a few Times using Kaikoen when he had the Supersayan State active,
and it was either only in Fillers, against Paikuhan in the Afterlife,
or in One or several of the Movie's, was it? In other Words: " Non-Cannon " ! It's not a Proof that Goku would use this in the real Series. The Movies are not that much authentic to the Series,
and it's the same with the Fillers. Otherwise: Why did Goku N.E.V.E.R. use the Kaioken as a Supersayan - against Cell - or Boo, otherwise? I guess it's like this.