Thailand probably produces a lot more rice and exports it a lot cheaper by this point than the Kiyungu, and definitely the Papuans, can export their foodstuffs. Population and labour force sizes aside, I don't think that something like sago even compares to Thai rice exports - it is far less nutritious and desirable than rice and takes too much labour to produce the end product. The quantity and price of Thai rice definitely makes up for the extra shipping distance in my book.
In terms of raw energy yield, white rice and sago pith are comparable. White rice has about 365 (kilo)Calories per 100g, sago pith has around 355. Rice does have more protein, but not enough to be an adequate protein source in itself. Both of them would need protein supplements from elsewhere; wattleseeds, eggs, fish or farmed animals, principally. Both of them have limited other nutritional value; sago has a bit more iron, rice has more B-vitamins, but again not enough for a complete diet. In practical terms, either of them provides the basic energy needs but protein, fat and micronutrients need to come from other sources.
Sago is a useful plant as an export crop since is grown in areas which are otherwise of less use for agriculture, and the labour requirements in comparison to agriculture are low. I'd expect that the New Guinea lowlands could adapt very easily to ramping up sago production as an export crop, using marginal lands, while feeding themselves from their own lands, and trading for desired goods, to everyone's mutual benefit. This makes it pretty cheap, too.
In calculating sailing distances, well, much of it depends which port is picked. I did some rough calculations using Cairns (the middle Nuttana city) as the origin, and Madang on the north coast of Papua New Guinea. A lot of the sago harvesting will actually be closer, since it tends to be around the Gulf of Papua, so if anything this is on the high side, but it will do as an approximate figure. The sailing distance from Cairns to Madang (round trip) is 2580 nautical miles. In comparison, the sailing distance to Bangkok is 7446 nautical miles, or a little under three times the distance.
In other words, the Nuttana could bring in sago from PNG almost three times as fast as they could rice from Bangkok. To me, this suggests that the Nuttana will turn to sago for the bulk of their food inputs, in combination with what can be obtained from the Kiyungu (who also produce food surpluses relatively easily). Which is not to suggest that the Nuttana won't be buying rice. But at least in terms of where things are now, it remains a desired crop for the wealthy rather than a staple for the Nuttana working classes.
I'd also expect that - assuming that the Nuttana survive the Hunter and his times - their population will grow, and it will exceed what can be reliably supplied from New Guinea. At that point, rice imports from Thailand and/or elsewhere will begin to look desirable. But I don't think that they're there yet.
They definitely can industrialize / mechanize the process and eventually would IMO. The drying process shouldn't require much labour if it's sun-dried or flue-cured, you just need people to lay out the harvested leaves and gather it in the end, and for the latter you need people to feed in fuel. Grinding the leaves can be done with machine, no matter how fine or coarse a grind is desired. There's not much processing involved after that.
Does the fuel need to be particularly good? As in, does it need good hardwood timber, sawdust, or will any waste fuel do? (In the latter case, they may use sugar cane waste products).
I am talking about trading with Europeans in Asia. No one in Indonesia and SE Asia were huge sugar exporters during this period, and in fact sugar cultivation and processing only reached large scales in Indonesia by the late 19th century, under Dutch colonial stewardship. The Nuttana have the upper hand in sugar production over most states in Asia. Remember, with the ramping up of sugar production in the New World and the flooding of the Atlantic trade networks with excess sugar, no one had a monopoly on sugar. No one would mind the different EIC's buying sugar from the Nuttana and either reselling it in Asia or back in Europe, sugar was too in-demand that no matter where it was sourced from it would make good profits in Europe. The Nuttana definitely stand to make some tidy profits by taking their sugar to Asian ports which see a lot of trade traffic from Europe and trading for European goods or whatnot.
Ah, in terms of trading to Europeans to onsell to European markets, that's possible; I was thinking in terms of local markets. That said, the demand in Aururia and Aotearoa is high too, and can pay pretty well. I'm not sure how much sugar would be left over to sell to Europeans. That would depend in part on the relative prices of sugar in each market, and also on how much sugar the Nuttana can actually grow per year. I need to crunch some numbers on that.
Oh, that's great. Especially the reference to rose myrtle, which I hadn't come across before (or at least, not looked at in detail). Now there's another potential spice I need to explore. First by trying it myself.