Interesting combo
obtusisepalum is a high elevation species requiring daytime highs of mid 70's and night time lows in the mid to high 50's no dry rest. The canes of this species can get over 3 feet long

lawesii requires daytime temps in the low 80's and night time in the low 60's also even rainfall. Canes 10 - 18"

Instead of mounting you could use a hanging pot but it looks like both these species need a good temperature differential between day and night and no rest period. I hope it takes more after its lawesi parent in size for you