The pulse and the drop should work for series builds, I'm sure they have alot of room. Pulse might be a little trickier, I think the deck is a bit crowded with the pipes on the top but probably just fine.. my personal favourites for series are the Kennedy 24 2-post and the Mini Temple from Vaperz Cloud. I REALLY want to get a Temple neutral-post but I don't have anything 30mm yet.. been on the look out for a neutral post RDA in 24 or 25mm that isn't the Neutron.
For builds, I like kanthal or nichrome fused claptons that are around 0.30 to 0.33. Kanthal is kinda nice for series, a little bit extra resistance, and the extra ramp up time vs nichrome isn't an issue on series. I don't recommend pushing it below 0.3, but I've done 0.25 on the Cricket II with no issues and solid batteries. I wouldn't dare go that low on one of my series mechs though, 0.3 is the hard limit I set for that. 0.3 is still ROWDY, 0.25 is a little too intense and a little too low to be worth it. I'd start at 0.5 and work your way down to 0.3 and see how hot you prefer it to be.
I definitely recommend the cricket II if you want to try series, it's been my preferred way to vape ever since.. the vapour production is intense, and the perfect throat hit for me. The vapour pours out like cream.
I do still love a good tube mech, but series is my favourite hands down. Just be careful, it's a lot of power to tame, and safety is the most important thing.
PS, I use LG HB6 30a 1500mah batteries.. if you run 0.30 series at 8.4v, then that's 28a. Definitely doable for VTC5a's as well I believe, especially after voltage drop, but just be aware.