The leaves and stalk are going to add very little to the quality of the oil but a lot of bulk to the mix so you will need a lot more solvent and end up with a diluted oil. Better to use the leaves in your smoothies and the stalks for marshmallow sticks around a campfire.
Using a polar solvent like ethanol/ISO will absorb any water in the buds and dilute it making it less able to dissolve the oils you are after. For wet bud a non-polar solvent like butane/petroleum ether/hexane is a better choice and they won't absorb water which will end up on the bottom of the mix and can easily be separated out.
For top quality RSO the bud should be very dry, ground up fine and cooked in the ethanol for a while before straining and evaporating. If it's for smoking then the QWISO/QWEtOH method should be used. Basically everything is kept in a freezer then the ice cold solvent poured into the cold, ground up pot and strained within a couple minutes. Do a search in the forums for more detail.