For what it's worth, you may want to consider the longer barrel if you're thinking actual belt carry. With AIWB I've found revolver barrels to 4" make no difference to concealibity and in some circumstances are actually even more comfortable than a snub of the same frame size.
Here's Skeeter Skelton's thoughts on barrel length, including 'belly carry':
https://web.archive.org/web/20190801...%20Barrels.htm
When I went to pull up the article I found the owner of darkcanyon.net has sadly passed and the site is no more. It lives on in the Wayback Internet Archive :-(