Manta RTA - Double Coil Deck
If you want to vape around 0.3 you need two coils each 0.6 Ohm.
Zivipf is a good choice as you are located in Germany ->
Zivipf.de
For me Kanthal has the best flavor. Then NiChrome and last SS. SS is good to use in TC.
Fused Claptons with a small outer Wire diameter (0.1, 0.08 mm)
If mechanic please make sure you have good batteries. 0.3 is around 15 Ampere.
Regulated it would start with 50-60 watt.