I suspect that Marmalde will do fine on Lev. The hardest part will be your learning how to use an insulin that is very different than Lev. For example, you do not slide the pre-shot dose. In fact, pre-shot is important only to the degree that you'll know it's safe to shoot. Dosing decisions are based on the lowest value in the cycle. Depending on whether you decide to follow Tight Regulation or Start Low Go Slow will dictate how low numbers need to drop to warrant a reduction. You hold the dose for at least 3 days to evaluate the effectiveness of the dose. Because Lev is a depot type of insulin, doses need to stabilize. For most cats, the nadir on Lev is at around +8.
There are any number of other details but in many ways, it's more of a challenge for a caregiver who has used a shorter acting insulin to switch to a long-acting, depot type of insulin. And we'll be here to help you wrap your head around the changes.