NO. HE IS NOT OUT OF THE WOODS. This may be a food spike from the high carb. Just so you are aware, a true hypo on Lantus can require 16 hours or more of constant monitoring.
If there is any way to get strips, get them. If there is anywhere open, even if it means buying another meter, you need to be able to test if at all possible.
If you can't get strips, your safest bet may be to go to an emergency vet and have them monitor your cat until they feel it is safe for him to be back home. Without strips, there is no way to manage this at home.
However, we don't know if this is a true hypo or if your cat was simply running in low numbers. A 35 at 12 hours could be a late nadir. If you were shooting overlapping doses, we don't know what's going on. It could be a hypo or it might not.
I know that you said you have had good instruction and are knowledgeable in the use of Lantus. However, I want to underscore that once this situation is under control, that you read the starred sticky notes in the Lantus forum. I'm not convinced that you have all the information you need about the use of Lantus at your disposal.
(NB: in my earlier post, I was NOT suggesting that you use a short acting insulin. If you think Lantus can be tricky, a short acting insulin used incorrectly can be lethal.)