I have been moving stuff from my 20 year old UK portfolio to US based on future plans. ETF's are quite a bit cheaper in the US and there are more of them.
Im basically going into VWRL which in the USA is VT. But will tilt a little towards VXUS which is VT less the US bits on the basis of valuation.
I think only VWRL is really required as it will rebalance itself over time anyway. If the US crashes the proportion of US stocks will be reflected in the basket. But I like to dabble a little
![Smile :)](./images/smilies/icon_e_smile.gif)
Starting over in the UK VWRL would be all I think is needed. (Maybe iShares or other provider's equiv as well if portfolio is large enough for third party risk issues. Fraud/Regulatory/Hack/Fire/Flood etc)