I mix my lytes with apple sauce. I like the thickness of it b/c it's harder to spit out.
I use old wormer syringes so I don't know what size.
I only dose at a vet check, right before we leave. I do it after the bit is put back in her mouth. I do not dose the week before, the night before, the morning of. I overlyted my previous horse once. Never again. My horse has had no issues dosing the way I do. We compete in CA where it got 100 on our May ride.
No chasing. The leftover lytes in their mouth make them thirsty so it encourages them to drink ASAP.