Sorry, to make a bit of a jumble of the sequencing, but the post on the acro forum was getting very specific to Eddie and the content on Lantus vs Levemir is appropriate here.
The 70% reduction is temporary. The reason we do it is that some cats have very strong reactions to the switch. I'd be especially concerned in a cat with IAA cause the new insulin can trick the antibodies at the start. If we find the dose is too low right away, we can fast track it back. Typically the Lantus and Levemir doses end up being relative close to each other, though not necessarily equal.
The only downsides to Levemir for you, might be the later onset and nadir. Typical onset is +4 (can be 3-5) and typical nadir is around +8. But of course can be earlier or later. You have to figure out how that works for your schedule and whether you can make it work. Both Neko and I loved the new schedule. The later nadir meant she could get snacks up to around +9 without impacting duration. For me, I get up around +9 4 days a week for a workout, so it was easy to add a "nadirish" test into the mix. Neko also nadired more in the +9 to +12 range on Lev.