seems to me your doses are off. deca works best at 2-2.2 mg per lb of bodyweight. If your 150 lbs you should not be near AAS.
PLease post your entire proposed cycle, including PCT
Also since deca is highly supressive, I would say as a rule test dose should be 20% greater (mg /mg) than deca. Of course, this needs to be adjusted based on your goals and experience. A Test E 500 mg/wk and Deca 400 mg/wk makes much more sense IMO.
To answer your question, there was a thread a while back showing how twice a week injections do, IN FACT, keep your "levels more stable" and with that in mind twice a week injections, every 3.5 days, is best