Treatment of US Dividends & witholding tax when filing Income Tax in Ireland

Hi Folks,
I have searched "US witholding Tax" but could not find an answer. The returned posts are from ~2007.

I have a couple of questions that I hope you all can advise on:

1. Dividends from US stocks are taxable as Income but how is the US witholding tax treated? Is it deductible from the filed dividend amount?
2. If no then is US witholding tax refundable? (I'm Irish, living in Ireland. I am W-8BEN registered)
3. The Dividends I receive are related to RSU's and are automatically reinvested. They need to be declared as income regardless of the auto reinvest, correct? It makes no difference?
4. Can I deduct trading expenses against Dividend income or is that something I should be deducting against Capital Gains?

I think they're the questions I need help with but may return to the well depending on the answers I get here. Thanks in advance Folks.

1. Total of the gross dividend(s) has to be declared. You get tax credit of 15% of gross automatically from Revenue
2. Any withholding tax above 15% is reclaimable from US Tax authority. If you file a W-8BEN, then only 15% should be withheld
3. Yes, dividends reinvested have to be declared and are taxable
4. No, trading expenses are not allowable against dividend income. Some are allowable for CGT purposes

That's great - thank you @jpd