Thanks for the comments. Thus-far there seems to be little experience of using the FT891 in the field.
Yes the last few seconds of audio on the video suggests that when the audio amp is only supplying headphones or ear buds, the quiescent current will be <1 Amp. That is good, I can cope with that.
Regarding the ability to operate down to 10.8 Volts on the supply rail, that seems to be unproven, but I know a ham locally with an FT891 so a real test is possible.
Regarding the close in dynamic range, once upon a time I had a TS520. That has a measured Dynamic Range of 52dB. It had the worst RX I have ever owned. By comparison, at home I use a TenTec Orion II. This rig has a measured close in Dynamic range of 95dB. In comparison tests on busy frequencies it is chalk and cheese with the FT857.
I agree that the root cause of the difficulty is separating Sota stations in a pileup is unique to the way we advise our QRG. The callers tend to be nearly coherent and no matter what the dynamic range will we split them up. Roy G4SSH with a lot more experience of CW operating always called me a few 100Hz off frequence, sneeky but effective. That said I would like to try an FT891 in field conditions to see how it performs. The other alternative, as discussed, is the KX3, or similar, with a measured dynamic range of 107dB, I believe this has the best RX measurements for any portable rig.
I take on board the need for self training for picking out calls, that is a good line to go down. Remembering the frequent chaser calls is also very helpful when filling in the gaps. SP9A** , **0B and ***LEY being examples.
PS, I am a Yorkshire man by birth so I have a built in adversity to spending money, particularly my money!
Thanks for the information most appreciated. Watch this space.