Hi I'm starting a Saim-Hann army (my first 40k army) and I'm making it 750 points.

I have decided to include:

3 Vypers with starcannons and crystal targetting matrix, Thats 225 points and also a waveserpent to carry either HQ if i make it on foot or some other infantry CC unit (maybe scorpions or banshees)

So i wonder should i go for the more expensive jetbike HQ to keep him and his warlocks mobile or should i keep them in the wave serpent to make them mobile.

I also wonder as the units i have now chosen are strong against small numbers of troops, but not very effective against large swarms what more units should i get in order to be able to fight against a large spectrum of opponents?