FTC - UK taxes paid on US sourced dividends

In the future I will be a US/UK dual citizen resident and domiciled in the UK. So I will be taxed on my worldwide income by both the US and the UK.

I plan to avoid PFIC and invest money in US Exchange Traded Funds that are UK reporting. My income will probably be in the UK basic tax band so dividends would be taxed at 10% (actually 0% if we apply the notional 10% tax credit). However, the treaty gives the US the right to tax US sourced dividends at 15%.

So under UK domestic rules as a basic rate tax payer I pay 0% tax on my dividends, there's no FTC required and I pay 15% in the US. So no 1116 to file I suppose. Also under the treaty my UK tax bill would be 10%-15%-10%(notional tax)....which we round up to 0%

If my income was larger and I had to pay 32.5% UK dividend tax, but the effective rate would be 25% (because of this notional tax credit thingy) so under the treaty my UK tax due would be 25%-15% =10%.

In this case how would I go about applying the treaty on my SA106? so that I only 10% tax on the US dividends. Also I assume there's no need to file a 1116.

Am i right in thinking that if I keep my worldwide income within the US 15% tax bracket I will  pay 0% US tax on dividends? Also that level of income will make me a UK basic rate tax payer so no UK tax would be due on the dividends.

This means that if my income is only from US qualified dividends and I they are less than $35k a year I pay no tax in the UK or the US . Combine that with a ROTH IRA and you are really laughing at the tax man.