[LAU] JACK clients at different period sizes

Hi, I have a medium-sized Ardour session with a couple of plugins on most tracks, in which I'd like to record some additional tracks. Due to the number of tracks and plugins, it's not possible to run Ardour/JACK at very low latencies. The same machine (and the same sound cards) is also used for monitoring for the whole band, using a huge instance of JackMix. This needs to be run with as little latency as possible (128 frames per period, tops). How can I solve this dilemma? Ardour's latency doesn't really matter to me, as long as newly recorded regions are properly aligned with existing material. It might also be an option to run Ardour on a different machine via netjack, but as far as I can see the period size of a netjack slave is tied to that of the netjack master. It also seems doubtful that Ardour would be able to do correct latency compensation in this scenario... Any suggestions? Is there any way to run run a second, high-latency JACK server piggy-back on a low-latency server? Thanks, Dominic