Use a highly refined vegetable oil, like Wesson and add 5% BA. Do not even try to make 200mg/ml prop. It will most likely crash and be very fucking painfull if you can make it stay in a solution. Everyone wants to get all fucking creative when they make their own shit, but trust me just stick to the concentration that you would normally buy from a pharmacy. Ex Cyp 200mg/ml, deca 200 mg/ml, Prop 50- 100mg/ml. It is so simple any moron can safely make sterile injections just don't try to play mad scientist with your powders and you'll be fine. Also use very simple sterilization techniques, if you have been injecting steroids and have common sense you should be fine and 5% BA will kill anything in oil anyway.