Congrats on your SV, Laska, yddragon Great progress
Visceral fat: I totally agree with Suzanne that everyone should aim to keep this low for good health - regardless of whether they have T1, T2, healthy insulin metabolism, whatever.
For headaches, same tip as for 5:2
Have a teasp of Marmite (no bread) or a tbsp of unsweetened soy sauce. This replenishes the salt & other minerals that you lose with the very reduced food & the extra water.
Milk:
I recommend replacing milk with unsweetened almond milk, which has only 2 cals for 100 ml, almost zero carbs.
Daily carb limit
Mosely & Prof Taylor specify what to eat and what to cut out, but don't give a carb aim.
Since they emphasise BSD is low carb
. I'd recommend 100g as a maximum daily limit on maintenance
. I'd aim nearer 50g in the 800 cal weight loss phase, or on the FDs for those doing 5:2 BSD.
The weight loss & metabolic improvements described in the book are probably only feasible if you strictly follow the BSD and totally cut out starches - grains, bread, baked goods, crisps, rice etc - and alcohol.
If you are not quite that strict, but at least average below 1000 cals, you should still lose 2-3 lb per week (estimating from online reports & your probable calorie deficit)