Charging/Testing with Hgbp

New to working on large tonnage systems (comfort cooling) with fancy controls. Wondering what state the hot gas bypass should be in when charging/checking system. My guess would be to isolate the valve and charge to spec but I'm not too sure. Wondering about the unloaders on the compressors aswell and if they should be on/off for the aforementioned scenarios. Have limited info on the unit itself due to manufacturer going out of business/selling out over 15 years ago... so not a lot of data made its way online it seems. Thanks