U should probably do 10 weeks and about 500mg test per week and maybe 300-400 deca per week....For your first cycle its recommended that you only use one compound at a time just incase...Because, if something goes wrong (for examples your nipples get tender or lump growing in breast tissue) You will not know if the Test was the problem or the deca..
Also you should stop the deca one week before the Test so you can start your PCT 2 weeks after you very last shot and it will make it so your blood levels are more stable... This is because the Ester in deca is longer than the ester in test and you want to balance it
Just my 2 cents mang