Ok brother, heres the thing, gh and test are two very different things. Your body's natural production of both begins to decline with age, which it sounds like you are very well aware of. If you had to pick one or the other, I would start with test. But I would not suggest sust. It is make of several esters of test. Some of them are very fast. You want your hormones to be stable. Stable hormones produce fewer side effects. In the US, Dr's use Test Cyp. Cyp or Test E are about the same and either would work well for your needs. Everyone needs different dosing. I would start with about 200mg to 250mg every 7-10 days. Somewhere between 100-300mg EW will probably be good. You may also want to use an AI like aromasin, which will block conversion from test to estrogen. How much you need will depend on your estrogen levels. So I would suggest running your test for about 4 wks and then getting labs done to see where your test and estrogen is. Then if needed, add in the arom. Test will be the number one thing to make you feel yourself again and improve your quality of life. Lets put it this way, all the things that make an alpha male are realted to test, IMO!
Now for GH, it can be amazing stuff, especially for older guys. I would suggest getting the best quality GH you can, I go with Hyge and you will want to run about 1.5 to 2iu a day for HRT. For older guys, the effect may be seen quickly, fresher skin, thicker hair and better sleep are things some guys will notice within a few wks to a month. In the bigger picture, you'll see less wrinkles, tighter slin and less body fat.
Now to go for the gold...Combining test and GH works very very well together. So if you can, I would suggest them both. Best of luck brother, and if you (or any other readers) are interested in hiring me to help with a diet program, including nutriton, cardio, training and super supplement use, contact me, here at Naps through the Next Level Nutrition page.
Best of luck buddy and I hope this info helps. If you need more questions answered, send them over, and I'll get to them as soon as I can.