I think it realy comes down to whether you have the $$$ to invest in a mass cycle of GH for the proper amount of time. 6iu's+ for mass is best IMO not knlwing your stats (4iu's or less will work, but not optimal for mass gains, better suited fat loss, hardening, body composition, etc.). Now if you have money to spare, it definitely won't hurt, LOL.
Money aside. You've already said you are getting better gains than you expected from your current cycle. Plus you would be starting having already been into this cycle, i don't know how much longer you intend to run this current cycle but maybe wait until your next cycle to get a good 12-16 week run of GH which is optimal IMO. You can stock up on GH and get a good high-dose/long duration cycle next cycle.
Also, GH isn't as good a mass builder as good old fashion AS. If mass & strength is your goal (as stated in your post) you are better off spending more money on AS. You are running a pretty high doses already but if you are willing to add GH you can alternatively add more AS to your current cycle along with extra ancillaries (arimidex, letrozole, anti-acne meds, etc. if required). In addition to your current test and tren you can add EQ or deca for some extra mass and strength gains (plus a little more test). Again, GH is good but nothing special as far as mass/strength gains versus AS.
If you are at your genetic limits and have done higher amounts of AS than your current cycle then GH could be that extra edge. I've known a lot of bros who have taken more AS than your current cycle before they moved on to GH. So unless you have money to burn or have stagnated/maxed out on AS, I say take the gains you are currently enjoying and save the GH for the future and concentrate on the training, diet and sleep and if really going all out add AS over GH. I personally experimentd with GH and had really bad water retention problems and carpel tunnel syndrome like complications. Just my 2 cents bro, good luck...