Insulin measurement:
It's not easy to measure insulin because of it's short half life in the blood. Cpeptide and Insulin are produced in equal amounts but C peptide has a longer half life. This is why it tends to be C peptide that is measured.
Testing for insulin levels is problematic
Natural insulin and c peptide are also a function of blood glucose levels ie they will be higher when glucose levels are higher and vice versa hence they are variable
Insulin declines in T2 but the rate of decline and the starting point are extremely variable . It has also been observed observed that C-peptide may fall but then return to higher levels in the same person.
The urinary c pep/creatine ratio test that Patch has is useful for distinguishing between T2, T1, and MODY . His values were right in the middle of those for people with T2 (not on insulin) but note how they don't really differ from the levels of non diabetic controls (the difference is presumably that there is not enough insulin to overcome resistance).
Note also that the ratio goes down when the T2 takes insulin. I assume this is because natural insulin is suppressed. Compare this to the levels for people in the early years with T1 (ie similar)
http://www.diabetesgenes.org/content/urine-c-peptide-creatinine-ratio
Academic,
I don't think that the study that you referred to tells us much. I do know that we have 90 years experience with injected insulin and it has prolonged lives, not only in T1. Until the 1950s this was the only treatment available to those who were probably T2s (not actually defined then so some may have had LADA) . As soon as insulin was introduced these peoples life expectancy increased. (Joslin quotes an average life expectancy of 8years for a person diagnosed aged 40-59 in the Allen (starvation diet) era and 15.6 years in the post insulin period from 1944-49)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2037674/pdf/brmedj03598-0003.pdf
I've no doubt that you will find that some people using injected insulin will develop some problems and indeed it may be discovered that excess insulin may play a part in causing cellular damage . However, these people and that includes me would have more severe problems caused by raised glucose levels
Is there a better alternative available?
(and I agree that reducing insulin resistance is an important aim for some but this will only be a possibility in some cases (weight loss certainly helps but this doesn't help someone who is insulin resistant for other reasons ? genetic )
I also think that good education into the effective use of insulin is lacking, especially in T2 (how often do we read of T2s and even T1s being put on insulin with no real help) It's not much use using insulin if it's not used effectively.