I'm afraid that your questions are unanswerable.
It's a case of trying LCHF and seeing what works for you.
Some people find the weight falls off them at 50-80g carbs a day.
Others (me) need to be below 20g carbs a day.
Some lose weight faster the more fat they eat.
Others calorie count too.
I think your plan to go strict then increase sounds workable, and if would expect it to do what you want. The New Atkins offers a very workable plan for this, if you like structure. And you can always fine tune your fat intake to your personal requirements.
Is there any chance that you diabetes and weight may improve dramatically if you manage to get off the steroids at some point in the future?
Good luck.
I'd love to hear how you get on.