Hey Vincent!
Welcome to the LADA club :lol: There are several of us on here at varying stages of the condition. Many stay on diet and oral meds for 4 years or so, but eventually, all LADAs need insulin.
In my own case, I went onto insulin within a year of diagnosis - intermediate (basal) in very small doses initially but rapid-acting within three months of that. The problem with LADA is that it is the first phase insulin that is missing but the basal is still quite strong in the early stages, so fasting and HbA1c come back with good results and docs tend to say you're 'mildly diabetic' - my consultant even offered to undiagose me :crazy: (I was misdiagnosed as type 2 initially, as many of us are). So, you should test Fasting, before meals, 2 hours after meals and at bed time - your docs will probably disagree! You need to know what is happening after meals, because that is the danger area for LADAs. If you are spiking after meals, you need to go onto small doses of rapid-acting insulin. They will always try oral med forst, but these will either not work at all, or work for a short time and you'll see your post meal BGs gradually rising.
There is mixed evidence on how to preserve the remaining beta cells, but there is growing evidence that early introduction of insulin can help and oral med that stimulate the pancreas to produce more insulin (e.g. Gliclazide) can speed up the progression to full Type1. For me, the intermediate insulin was miraculous. I started on 6 units and dropped that down to 2 units every two days and my BG was still dropping low. However, my post meal readings were still spiking high even on 10g carb. Hence the move onto rapid-acting. 3 years on, I have just changed to long acting basal from intermediate (I take 8 units a day split into two doses). Rapid-acting I take with each meal and adjust according to the carb contennt. That is a progression of my condition, because for the first year I was able to manage with rapid-acting at tea time only and manage without for a low-carb brekkie and lunch. Having said that, I still have some pancreas function - my natural insulin is stronger some days than others, and i still have the natural ability to correct lows, so I don't tend to have dangerously low hypos.
Personally, I think the key to it is getting onto insulin as soon as you are happy to and certainly as soon as your BG starts rising after meals, and cutting as much carb from your diet as you can tolerate. Keeping your BG as close to 'normal' as you can manage safely is probably the best way of preserving beta cells for as long as possible.
Not sure if that helps as we are all different and there are other LADAs on the forum with a different view point.
Take care and keep asking questions.
Smidge