Really, as I thought the PON itself was limited to 2.4/1.2Gbps and all connected ONTs contend for an optical slice of that?
The trial was looking at both 1.8 and 1.2Gbps download speeds that rely on low neighbourhood contention to achieve it, but the downstream prioritised rate remains unchanged at just 110Mbps. I don't think the trial included any addition bandwidth to the local PON.
Most folks don't actually consume that much, Robbie. You're talking perhaps sustained rate of 5-6 Mbps at peak time.
A very elementary capacity planning rule is that you cater for the sustained peak time load, add the top burst speed that you're selling and maybe a bit of overhead.
32 x 6 = 192 Mbit/s. Add a 1.8 Gbit/s service you're at basically 2 Gbit/s. There's a bit of overhead. Will a 1.8 Gbit/s customer see the odd time when they can't hit maximum speed: sure. The overwhelming majority of the time they'll be fine.
Google Fibre are selling 2 Gbit/s download, 1 Gbit/s upload on GPON and it's mostly fine. Yes, the burst speeds are high but the bursts are usually really brief because folks can get what they want to done much more quickly.
My own experience was that the rest of the PON, 31 connected homes, consumed a couple of hundred Mbit/s. When I tested I hit 2.1 Gbit/s nearly all the time. No reason to think that cohort were abnormal. There are always going to be outliers where it's not an option to sell a gigabit let alone 1.8 but for the most part it'll probably be fine for now. When it isn't they can build an XGSPON overlay.
