By measured delivery. One mRNA strand produces one protein. The ribosomes, which are the proteins responsible for converting mRNA into proteines, cut the mRNA into its constituent blocks, which then goes into the pool of nucleotides ready for incorporation into a new mRNA transcribed from the cells own DNA. One mRNA strand yields one molecule of insulin. My idea is to produce enough insulin for a baseline load - thereby avoiding the spikes in insulin caused by injection. Those spikes are of course not present if you have an insulin pump.
THIS is ALL speculative - it's been 30 years since i opened those books (except for a few curiosities).