SLGS the dose is held for 7 days however sometimes we need to do things differently when a kitty is stuck in these numbers until the break through dose i.e. at least some blue shows up. However, you have been raising his dose too soon even for TR. TR is an aggressive protocol as written and doses are held for 6 cycles unless there is a medical condition that might warrant raisin it earlier. This is especially for lurkers to understand. This being said and our favorite saying here is ECID.
I read through the previous condo you had linked in regards to Rudy being on 4u of Prozinc so understand the fast tracking a bit. I see you raised his dose to 4.5u tonight after only 3 cycles of 4.25u. While not recommended I think you are fine and test enough.
Please hold the 4.5u for a minimum of 6 cycles. Lantus is a depot insulin and takes that long for the depot to fill and see what the dose can do. Not sure if you've read this sticky but it helped me understand Lantus
What is the Insulin Depot
My Doodles became IAA (78%) almost a year after he was a well regulated kitty and we hit 12u of Lantus. Every kitty gets to a dose that works for them so try not to be concerned at the amount...they need what they need. Easier said than done and we all understand what you're going through so hang in there and keep posting.