I am an applicant myself, so no official committee or anything
But I would say definitely go with your second option mate, you have the most chances writing the GMAT on your coming date, who knows, maybe you score what you want, and if not, THEN you could contemplate not sending that score and gunning for the third round
If you don't mind taking the exam twice in such a scenario, go with this. Again you could do well on the first shot !
As I said I am only an applicant, but R3 is almost like a bonus round to be even considered a real one, i've heard adcoms say they number of students admitted in the last round varies widely from year to year, sometimes being as low as ten or lower ! That's from memory so I MIGHT be mistaking, but I believe that's the consensus
I'm sure others will give you some valuable input as well