Yes, use tape out on the Jolida. Tape out is "fixed" meaning regardless of where the volume is set on the Jolida the level coming out of the tape out is the same. This way it doesn't affect the volume on the other amp.
It will work fine and as you said no Y adapters needed. Let us know how it works out. Also, enjoy the flexibility of the two volume controls you'll have to make things sound to your liking.
If you want to be anal you can connect a tuner, tune it to "dead air" and measure the outputs of your amps with a voltmeter (set to AC) and tweak the volume control(s) to equal the output of each amp. You'll at least have somewhat of a reference for where each volume control is in relation to the other for equal output. In the end I still say set it the way you like it!
ET
It will work fine and as you said no Y adapters needed. Let us know how it works out. Also, enjoy the flexibility of the two volume controls you'll have to make things sound to your liking.
If you want to be anal you can connect a tuner, tune it to "dead air" and measure the outputs of your amps with a voltmeter (set to AC) and tweak the volume control(s) to equal the output of each amp. You'll at least have somewhat of a reference for where each volume control is in relation to the other for equal output. In the end I still say set it the way you like it!
ET