Which kind of E-card apply to ?

I'm assuming you are an EU citizen

you cant apply until you are living here - you are not applying for residence, but informing the authorities that you consider yourself resident, and are proving you have the means to support yourself

no problem in getting self sufficiency version at first, and then working

Thanks GinG. I spoke to a residency expert just before Christmas. He indicated it would be a problem to be register as self sufficient and then start (self) employment. I was left thinking the whole process needed to be repeated iif such a change were to happen. I didn't see the need. Perhaps the expert was seeing two bites of the residency application cherry.