I'd find the derringer a bit fiddly, have a look at the SXK Hadaly clone on Fasttech, simple to build only takeas a single coil and at £12 a pretty good buy, I've got one - works flawlessly. The 1.5 ohm coil sounds fine and the muji is a safe bet, you could buy ready made coils but a simple roll of Kanthal from Stealthvape, a couple of screwdrivers and a pair of cutters and scissors would mean you can do as many coils as you want as often as you want and there are plenty of basic coil tutorials on youtube...