I have used deca successfully in 6 week cycles - but i would recommend you frontload the dose to get the best results from this drug. It wont begin to work till the 4th week otherwise.
I wonder why you are deciding to run the test for such a long time..
I know that when i was cycling i liked to use 6-8 week cycles. it allows easier recovery and allows more cycle per total period (per year or whatever).
You could frontload the test and the deca, run the deca for 6 and the test for 8.. this would be an excellent cycle and easier to recover from than 14 weeks on test, which i do not recommend for you at this time personally.
Deca really does seem to give the best results/side ratio at 2mg/lb bodyweight, so if you weigh 150lbs then 300mg deca would be nice - with 500mg test this would be a hefty first cycle IMO, but you will be happy.
I also liked to use single drugs for my first few cycles.. whether dianabol, deca or test - i used each alone to see what was going on.
Once i ran the three together i knew what was doing what to me in terms of gains and sides - so then i knew how to counter the sides or manage the gains without dropping the wrong drug or increasing the wrong one - or having to drop the whole cycle due to panic and uncertainty.
500mg test and 2-300mg deca - if both drugs are pure, then you are highly likely to have a potent rise in estrogen, which will likely manifest itself in gyno quickly.
Deca and test are a tittie boosting combo for sure.. make sure you run either letrozole or arimidex throughout the cycle, and taper it off after the cycle.
For a 6-8 week cycle (and a 2 week break post cycle before PCT) then a SERM/Nolvadex PCT will be fine for assisting recovery IME.
I think you will struggle if coming off a 14 week cycle however, again in my experience.
If you want to use HCG then use it during the cycle from week 3 to the end (wherever that may be) at either:
as you can see the total dose is almost identical to the three most commonly recommended protocols for HCG - between 600 and 750iu.
the cycle i proposed is the following:
Wk1-8 500mg Test Enanthate (250mg 2x/wk)
Wk1-6 300mg Nandrolone Deca (150mg 2x/wk)
(To frontload inject 725mg of Test and 500mg of Deca on the first day of use, then follow with regular dose)
Wk1-8 Arimidex 0.25mgED+ approx.
Wk3-8 HCG 250iu 3x/wk or as above detailed
PCT 2 weeks after last inject: 40/40/20/20 tamoxifen