snortin heroin how many g do i need

hello i had a small line elt nothing after 15min so u had another small line and still feel nothing so i came here to ask if anyone has a sugestion on how much i should do and/or whats the upper limit to not go over

about me i've been taking morphin pills for some months now shooting them too. when shooting i used ~150-250mg. i've only had heroin once where i shot a tiny bit but that was weeks ago. because i want to quit the needle i got heroin now which i want to snort instead. or would u say smoking would make more sense?

i hope for answers thanks in advance