First thing, I'm hoping you have done a good PCT for your most current cycle. Deca can be very hard to recover from, plus at 42, your test is on the decline. It can be harder to recover, the older we get. I would use HCG in your future cycles to help ensure your recovery and thus retain your muscle. Part of what you have lost has been fluid retention. I would expect to have been holding 8-15 lbs of water. If you lost a lot of weight right after your cycle ended, say in the first 5 wks, it was probably fluid loss. The better your diet, the more you will gain real muscle and the more you will retain after. but there will be a very sharp decline right after you come off. Don't let the fluid loss get you down. Its all part of the process. 2 steps forward, 1 step back. There is no magic combo that will get you huge. Its doing cycles over years and slowly getting closer to your goals.
There are drugs that will make you hold less water but you may not be able to make the same muscle gains on them either. Here is what I would suggest for a good cycle for a newer guy. Just remember that diet is the key. Do all the research you can about diet and learn what it takes to make your body respond. It can take time and experience to figure it out, but it's all part of the game. I'm available here at Naps Gear, in the Next Level Nutrtion section of the web site, if you are interested in hiring me to get you to your goals.
As for a decent cycle for someone at your level :
wk 1-12 (to 16)
Test E 500mg EW
EQ 400mg EW
adex .25-.5mg EOD
On the topic of GH, growth is a long term commitment. At 42 yrs old, you may benefit from it, even at low doses, but it's something that you want to use for a long time, at least 4-6 months. Longer if possible. It isn't going to produce big gains, and it isn't going to produce them quickly, but it will help to transform your body over the long run. 2-4iu will help with fat loss and over the long long haul, add to your muscle mass. Running it with your cycle will certainly produce more gains than when gh is run alone.