Maybe try
this calculator. It's a bit easier to understand. You don't need to take the negative exponent into account like you do on unit juggler.
0.5mtpa agreements are feasible. Freeport is constructing a 3 train, 15mtpa LNG export facility in the US and
here's an example of a relatively recent 0.5mtpa SPA they closed with commodity trader Trafigura. Operators, understandably, prefer to sell entire trains. For Magnolia that's 2.2mtpa each, so in that sense you're right about 0.5mtpa not being ideal for Magnolia. Mind you, I don't think holders here would mind too much if management inked a deal for 0.5mtpa. At least it would be one small step closer to the 6mtpa needed for FID.