In this forum, we start a new thread each day, so what you did was good - I just added the link so people could go back and get more info from your first post.
With the TR protocol, we use a weight based formula for determining the staring dose, (#kg x .25) which would be around 1.5, but we also take into consideration the dose of the previous insulin if there is one. TR has you hold a dose for 3-5 days before increasing and cats earn reductions when they go below 2.8 (50). For TR, you need at least two tests per cycle, the preshot and one other, and that includes the evening cycle, when many kitties go lower. The SLGS protocol means slower changes, holding each dose for at least a week and then doing a curve. The starting dose would be .5 units if he's on entirely wet food and increments are only .25U. SLGS reductions are earned when kitty goes below 5.0 (90). Some people can only use SLGS, you should chose whatever suits your personal situation. Kitties who get some dry food are limited to SLGS. I'm quoting blood sugar numbers for using human meters, which I believe you are. You can switch protocols from one to the other if you decide you want to. We just ask that people put either TR or SLGS in their signature so we know how to help you.
I think the main reason Tabby isn't feeling so good is his high numbers. I'd like to see him get into better numbers sooner rather than later. It helps regulation and the possibility of eventual remission if you can get his numbers into normal blood sugar numbers sooner. If you were following TR, I'd suggest an immediate increase back to 1.5 units, with at least two tests per cycle, then evaluate the dose after 6 cycles. It's possible he'll need around the same about of Lantus as he did Caninsulin. Following SLGS, you would hold the dose for a total of 7 days, do a curve, then increase by 0.25U if the numbers warrant it, which I suspect they will by your spot checks.