Personally, I would be looking at heading to Newbury for the G3 John Porter Stakes in mid April and then onto York for the G2 Yorkshire Cup in mid May. Obviously if he shows he is capable of winning at that grade then you can try fishing in deeper waters.
You could then either give him a break to avoid the summer months or head to France (for the G1 Grand Prix de Saint Cloud in early July) and then target either the G1 Grosser Preis von Berlin (early August) or the Ebor in mid August, then take in the Irish St Leger in mid September and the Champions Long Distance Cup on Champions Day in mid October (which due to quarantine processes would likely rule him out of a tilt at the Melbourne Cup).
Alternatively you could always miss Ascot and try Australia or even go for the G1 French St Leger in late October – there are so many options available to him on the flat, some are more winnable than others of course but I do think he is capable of mixing it in that grade if given the chance.