Bit confused with Phenibut Dosing

Hello, I know the side bar has information on dosing and i've also read many dosing regiments. I'm getting mixed info with some people using 500mg and some using around 3g. This will be my first time using. I dont want to get fucked up just social/anxiety free/have fun ect. I bought lift mode HCL 300mg pills so my plan was to just take two of those. I'm also going to class for two hours after I take them so should I be fine for that based on this dose and the onset time? Also i've heard about people shitting themselves, should I worry about this at a 600mg dose? Thanks in advance!