Deca and sustanon are both very long estered steroids. They will be in your body 4-5 weeks after you stop your cycle. Your plan on doing a bulking and then cutting cycle wouldn't really work because the bulking steroids would still be in your body when you want to start your cutting cycle.
Focus on one goal. When you try to do everything at once, you end up getting mediocre results. Run your bulking cycle, run a PCT, do a SARMS bridge and then do your cutting cycle. SARMS are great for increasing fat loss and you will actually lean out during the SARMS bridge. Then when you start the cutting cycle, you will already be in striking distance of pre-contest condition and won't need to suffer during your cutting cycle.
A much healthier option is to do as follows:
1. Run your cycle.
2. After your cycle run a good pct protocol such as the perfect PCT:
http://www.evolutionary.org/the-perfect-post-cycle-therapy-pct/
3. After the PCT protocol, run a SARMS bridge - such as the SARMS triple stack:
http://www.evolutionary.org/the-SARMS-triple-stack-protocol
4. After the triple stack, run a mini PCT. 4 weeks of the following:
clomid at 25mg/day
nolvadex at 20mg/day
HCGenerate ES at 5 capsules/day
n2guard at 3 capsules/day
5. Then wait 3-4 weeks, ideally get blood work done to make sure everything is in the normal range and start your next cycle.
With doing 1-5 you will continue growing off cycle and your natural testosterone production won't be suppressed. It is a healthier route all around.