Really beautiful well grown plant... I found out slow release to be important for multis ( using nutricote/Molcoat at 30 pellets/12 cm pot as a standard in addition to the normal feeding). Most likely because the slow release releases... a lot of ammonium.
It's funny too that about 5-15 years ago, most wild sanderianum were slow growing and easy to intoxicate with iron... I still have plants from that time, and iron toxicity is a very big problem. I got fresh jungle plants several times, and recently the new colonies are not susceptible to iron.
Rapunzel was sold by Azadehdel by the way, originally, and Alexander Voon was the collector in Sarawak (strange life, now he lives a few meters from Orchiata/Pacific Wide office in Christchurch !!!)..