Forgetting F-layer propagation – now unlikely this autumn on 6m – the best chances of 6m transatlantic propagation are the next 6 weeks by multi-hop Es.
For a decent chance we need lots of stations active on 6m WSPR on both sides of the Atlantic. Generally there are quite a few active stations in Europe (including the UK) but very few in the eastern USA. I find this hard to fathom.
Not much power should be necessary. Even a few watts ERP should be enough. 6m is a fascinating band and WSPR the ideal mode to “sniff out” short-lived openings.
Please, if you are in the Eastern USA or Canada , come on to 6m WSPR for June and July to help us see if the 6m band opens “across the pond”. Without stations in the right place we are wasting our time.