Hi, if you're still looking for seed, I may be able to help. I grew Rai Kaw Tok pumpkins this year and saved a handful of seed from one, and I'd be happy to share, but I am fairly new to both gardening and seed saving so I can't promise the seed is pure until I grow it out next year and get a look at what it produces. Both male and female blossoms were bagged with organza bags before they opened, and I hand pollinated the next morning and re-bagged for several days, but I did notice ants in the male flower and I don't know if they could have caused cross pollination since I did grow other moschata squash varieties nearby.
If you have room in your garden to experiment and would like to give it a whirl even with the chance it could be crossed, I'd be happy to pop a few seeds into an envelope and send them along for you to try out, (free of course, given the uncertainty) just let me know where to send. (As long as it's a USA address please, I can't mail internationally, sorry.)
I can tell you a bit about my impressions of the variety, if it helps. I grew Kang Kob last year, and personally I find the taste of Kang Kob and Rai Kaw Tok to be similar, though someone with more discerning tastebuds than mine might disagree. Savory and smooth. When I researched Rai Kaw Tok I saw it referred to as having a unique "spicy" taste by one source, which intrigued me, but I didn't detect anything like that myself. I also saw it described as sweet, which is probably subjective, (I may just be used to the super sweet types like Honeynut) but I have to disagree on that point.
I do have squash borers, and Rai Kaw Tok held its own against them in my garden, but so did Kang Kob, so the pest pressure might not be as severe in my area as it is in yours. We had an extremely hot summer this year (lots of 90f-100f days from June to Early September, those temperatures are more typical of July and August in a normal year) and that seemed to affect productivity, the vine didn't set many pumpkins until late in the season when the temperatures were more reliably on the lower end of that range, and by that time they had trouble ripening before frost. It was one of these I saved seed from, so I hope the seeds reached full maturity. They seemed to, but again I really won't know until planting. It got a lot more productive with slightly cooler weather, so it might have been much better in a different year without such an extremely long hot summer. Kang Kob did well last year in a more typical summer, though a bit slow to get started and it needed all of our long growing season, so I would expect Rai Kaw Tok might be more like that normally. I've only stored my Rai Kaw Tok pumpkins for 3 months so far, so I don't know if they're good for long storage yet.
I tend to be long winded, sorry. So that's a lot of text to say it's good, and I'll grow it again, but (in my own opinion) it's not so unique and amazing that you're missing out if you've tried Kang Kob but can't get Rai Kaw Tok.
If you're trying different moschata types for flavor, I did that myself in the last few years and I can also recommend Violina Rugosa butternut as one to try, it did pretty good for me against squash borers this year, and it might be my favorite for flavor so far, very sweet and rich. Its only real downside is that it isn't super productive. If you could get that flavor into a more productive variety, you'd have a winner for sure.
Honeynut was super productive and basically survived the borers by growing faster than they could attack it, the squash mature early too. Its very sweet and probably my second favorite for flavor, but storage time is short at only 1-2 months. It's small though so we eat them fast!
Tetsukabuto was the best against borers, completely unfazed by the nasty little things. Production and taste is good, but it's a hybrid so that's a big drawback as you can't save seed. I think it's a moschata/maxima hybrid? It requires cross pollination from another variety and the seed inside mostly doesn't seem viable, though I do occasionally come across one or two plump ones in a squash. I am going to try to bag some blossoms on it next year just on the chance I might get a viable seed, I figure there's no harm in trying.
I hope that's somewhat useful!
