Allow longer “Unused subscription close delay” inside Tvheadend client

hi,
Could it be possible to increase the maximun “Unused subscription close delay” to something greater than the default max 60 secondes?

This could be very handy for people that love frequent channel zapping Blush when having a bunch of tuners aviable.

I have 6 tuners and there are 6 muxes in my country, so when I start watching TV each of my tunner could stay tunned on a mux for a long period of time without issue.
This would allow super fast channel switching even for other clients.

I did try to manualy edit the pvr.hts/settings.xlm and set <pretuner_closedelay>7200</pretuner_closedelay> but it looks like then the client reset to default value.