I have now included vocalic alternation in my Kemmyn to SWF converter at my Bitbucket account.
This is the effect where many words that have "yw" in a monosyllable such as "byw" (alive) have "ew" in a 2 sylllable word such as "bewnans" (life). This was originally spelt "bywnans" in Kernewek Kemmyn, though in current Kemmyn, and Standard Written Form it is "bewnans".
I have also implemented the change from yw to uw in words such as Duw. (God)
Words with a stressed 'y' vowel in a polysyllable can also change to 'e', including words such as "benenes" (women). The singular is "benyn", and the plural is "benenes" in SWF, but was "benynes" in Kemmyn (at least until recently, I am not sure exactly which words changed in current Kemmyn, I'll have to find which month's copy of An Gannas it is described in...)
The sylabelenn_ranna_kw module has also been updated a little, to include more abnormally stressed words.
The revised output is at http://taklowkernewek.neocities.org/kernewekFSS/GwreansAnBysConvertedSWF.txt
If you haven't yet signed the petition encouraging the govenment to continue funding support for the Cornish language, see https://petition.parliament.uk/petitions/128474.