1) You'll have to prove the source is 'independent'
no i don't, you should have supplied the osurce for your work or i could charge you with plagerism. but then you credibility is hanging by less than a thread as it is.

2) Has anyone ever written about indulgences who was independent on the subject? If so, why?
why doesn't apply to this question as it would entail that other posters had the ability to read minds, some long dead and inactive, so you are very off base.

i would not accept a RCC version except for comparison value to see the differences and would most likely side with th eindependent view as they have nothing to hide, which many RCC people do.

by the way, indulgences is NOT a scriptural teaching and is a heresy but i will look through your stuff and independent sources but i am busy at the moment so it may take a few days.