You should start them both at the same time. However, it's just as easy to do a submerged start if you have good CO2 and ferts imo....no reason not to. DSM is just less maintenance I suppose.
Will agree with the growth here....my glosso/belem/hc/h. tenellum micro has almost completely carpeted my 20L in about a month (reset on 8/23) with submersed growth, good light + ferts + CO2 mist.Why would they dry off? I am sure you are adding water to keep the humidity up correct? Also the DSM makes since for Cuba (HC) because of the small root system, but I have grown o full carpet of glosso and DHG in less than 5 weeks submersed, just lots of co2, light and dosing