I would like to make my slony somewhat lazy. By "lazy" I mean
preferring less frequent updates in bigger packs. The factor to
optimize is network and database usage. I am OK with subscriber being
a few hours behind the master.

I played a bit with slon.conf, trying border values (on both sides,
just in case), like

   sync_interval=60000
   sync_interval_timeout=120000
   sync_group_maxsize=100
   desired_sync_time=300000

Is it going towards my aim? Can I do anything except that? Are those
truly maximums as config texts say, or maybe could be increased even
more?