Hi Mike
Yes - I did notice the stars were ever so slightly bigger at the end of the run than at the start. I tried another reprocess using the sharpest image as the base for the align in CCDStack, and it's certainly sharpened it up slightly again. A bit of a shame as I'd just spent $35 bucks on a print

...but it still looks nice printed.
I have a temperature compensated robofocus here... might one day adapt it to the Tak focuser and see about re-focus runs if I'm doing a long sequence. I'm just a bit loathe to add "even more cables" just now
Will hopefully be back at Wiruna for the June get-together.
Let me know how you go there - I hope it stays clear for you.
Regards,
Rob