Do you actually want to instruct?
If so, then do the instructor rating first. Not having a ME/IR will show potential employers that you are going to be around instructing for at least a little while, not running off to a jet job next week. Also, having a few hundred hours instructing behind you will make the ME/IR much easier.
On the other hand, if you are not planning on instructing for any length of time, then probably best to skip the instructor rating altogether.
FFF
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