good reference for pumila - Laelia pumila Culture
I've been growing a wide variety of pumila clones for over 30 years and tried all combos of potting media, light and temperatures.
Pretty temperature tolerant, in winter will rot growths if night temperatures are consistently in the low 40's or below, but occasional dips this low when plants are dry is OK. Grow best between 55-85 F with ideal 58-80 F. Somewhat less moisture in winter.
Mine do best mounted or in wood baskets with very coarse bark. They come from fairly dry areas, but almost always near watercourses in these areas. Similar to jongheana, praestans and sincorana, they are adapted to get moist almost every night from fog and mist and then dry out pretty well during the day. I find they do best for me if I water them either late in the afternoon or very early in the morning on an almost daily basis once night temperatures are consistently above 50 F. Everyone that tells you to make sure your plants are dry at night is not giving you very good advice for these species. They grow way better with a nightly moisture cycle.
I've also used sphagnum and clay pots, but found it tough to find the happy spot between moist and wet. Wet will kill the roots. Best I've done is to fill half of small clay pot with LECA balls and then 1/2 moss. This does a pretty good job and then you don't need to water them every day like a mounted plant, but every 2-3 days in the growth season and a little less in the winter.
Grow best in fairly bright conditions, but certainly will burn in full sun. Generally found closer to the ground rather than high up in trees, so don't need super bright light compared to larger sun loving Cattleyas.
There are lots of great clones from Brazil, many of which have very large flowers and will often have 2 flowers per growth. In the US, the plants that have made up our breeding stock are generally older clones with smaller single flowered plants. The Santa Barbara Orchid Estate has definitely done some line breeding and have historically had some pretty nice clones.