I generally send the Spyders on their way during my second turn after I've added two turns of Scarabs. I always move my Spyders first then my Scarabs. It's more of a old "tryanid" tactic of Hormagaunts with several monstrous creatures in the back. I've never had any problem with them. I always move straight up and try and get as center to the board as I can to have a wider threat range.
A Daemon Prince w/ wings and goods can run pricey but is going to be a bigger threat than a C'Tan because of his ability to keep up with the rest of the army, specifically the wraiths and the scarabs. I've played it once or twice and it really is a " Oh crap shoot everything I possibly can at him , Oh God"
As for fleet I was half a sleep

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I usually play pretty pricey Prince, but also I don't always take all nightscythes, because I have fliers already and mostly do it because I think three max is enough. The army is though a Dark Harvest list and a Khorne themed Chaos Space Marines list. It's a silly fluffy army I've played via proxy and on Vassal but it's always been super fun I would probably tell my opponent though as it's kind of weird and sometimes cannot be fun to play against. Points are usually 1850 to 2000.
I run a pricey Daemon Prince
Daemon Prince
Wings
Mark of Khorne
Power Armour
Axe of Blind Fury
Total : 255
Heldrake : 175
Chaos cultist : 50
Total : 480
Your load out with C'Tan comes to 450?
Also the previous is not "fun" to do but if you just want a "one off" game to run it, cool. The list I run with that though has literally no shooting except for the Cultist, the Heldrake, 1 Night Scythe, 1 Ghost Ark, and some warriors. So its really light on the shooting but it does have 10 Monstrous Creatures.