Hi Ashlee! welcome to the Lantus/Basaglar and Levemir forum! Sylvester is so cute! love him!!
HERE is a link from the FAQ page with some tips for stimulating kitties appetite. You may want to call your vet tomorrow if he is still not eating. Lantus is a little more forgiving for
when Sylvester eats, however he should have some food in his belly for when the insulin kicks in(also known as the insulin onset) a typical onset is +2 (2 hours after the shot) although every cat is different (ECID). 270 is not too low for a preshot, if you can, try and get a few more tests today to see how low the 1u is taking him. I saw on your main forum post that you're working on your spread sheet, looking forward to seeing how Sylvester is getting along