>My base airport's SID ends at FL70<
Miserlou, does that mean your SID is unrestricted climb to FL70, or is there an altitude restriction prior to this, eg. cross x at 4,000ft?
If so, then after the 4,000 ft restriction then you should be setting 1013.
If the SID is unrestricted climb to FL 70 then there is still an option to set 1013 before TA and, I say again, this may prevent a level bust if you omit setting 1013.
Would you st 1013 on the standby in this case if your MSA/SSA was, for example, 9,000 ft amsl?
>What if you get a "Stop climb at 4000'" instruction?<
Assuming you are cleared to a FL then ATC should be aware of this and the fact that you may have 1013 set (in theory) but since you would still have QNH on the standby why should this be an issue?