Glad you got it working right, well done! I just tested it and can confirm it's working, saved a screenshot [here](https://ttm.sh/tv5.png). 

I was able to to authenticate using  my credentials and verified I was allowed to post. Attempting to follow up on threads resulted in slrn spawning mutt to reply, so I suppose reply-to is the standard method to post comments (via mail, through a smtp -> http gateway)?

I noticed it's a bit slow at getting headers, so being able to download articles to a local spool (e.g. via slrnpull) would be a good option, but I wonder if other users would be ok with that.
Cheers!