Hi. This is my suggestion for future firmwares updates.
Th lp 16 should have a internal mixer with individuals level adjustments, for example I want to have in outputs 1 and 2 mic level signal and the 3-16 outs line levels. This adjusment level is necessary in order to conect an output to bass or guitar amps and avoid using reamping boxes. (I tried to conect an output to my bass amp and it sound very loud. (a bit disto[map type=HYBRID zoom=2][/map]rted)
The Lr16 has that function. You adjust the recording sensivity, then it would be great in Lp16.
The LR-16 has an input attenuator where you can set +8.2dBu or +20dBu input sensitivity.
As your request require hardware modification it cannot be solved by firmware update.
BTW. You can try to reduce the volume in the uTool mixer where you create the song. The default mixer level is 0dB in this case with full scale signal you’ll have 2 Vrms on the outputs. You can try to reduce the mixer levels and enable the post fader output in the menu, in this case you can drive your guitar amp from the LP-16 outputs.