I 'forgot' to give BFG his insulin shot one night, only realised when I found full syringe on counter next morning.

it happens.
Did you decide on the snacks? to help avoid the acid tummy?
I was writing the following on my tablet last night in bed and i run out of juice.
Just something to ponder with regards to feeding.
It's a great idea to feed regular snacks, I do every 3hours with George to prevent problems with acid tummy, he just gets his regular food spread out, but he is in remission now, so I don't have to worry about feeding late in the insulin cycle.
Feeding late in the Lantus cycle can affect duration, causing the ps numbers to rise, it's preferable to avoid this if you can.
What many folk who have had kitties with acid tummy trouble have done/do is to feed a very low/ zero carb snack at +9 something like a few small pieces of poached chicken breast, it shouldn't affect BG or duration, and should help with the acid tummy trouble.