That would address half of the issue, the reason it would be hard to load a slin pin is because the oil won't flow well through such a small gauge needle. Even if you do it the way you listed, you still would need the oil to flow through a tiny needle to exit the syringe. You could possibly heat it up to get the oil to flow, but even then the length of the needles on most slin pins is too short for a nice deep im injection.