The milestones for the 1500m piece are going to be slightly different from those during a 2000m test, but still in the same vein. Start your piece as we've discussed in the past: first stroke at three-quarter slide, second at half-slide, third at slightly longer than three-quarter slide. (We will practice this before Saturday.) Attack the next 10-15 strokes aggressively - you will not suffer from going extra hard here in the long term, and it's a great way to deal with nerves. But as soon a you finish that last aggressive stroke, settle down IMMEDIATELY into your pace and rhythm for the rest of the piece. It will feel too easy, but don't be fooled. It's very important to get into your groove early on. Focus on breathing, length, and relaxation.
I suggest throwing in a few 10s and maybe a 20 into your piece. By this I mean 10- or 20-stroke segments during the piece to focus on something. That "something" can be whatever works for you: sitting up tall, length, breathing, aggressiveness, loose shoulders, etc. Typically in a 2000m piece you'd do a 10 at about 500m into the piece, a 20 at about 1000m, and another 10 at about 500m to go. There are alternatives, such as 10 at 400m, 10 at 900m, etc. But the principle holds: marking milestones in the piece in a way that helps carry you through mentally.
For Saturday, I suggest marking similar milestones, with some adjustments. I think I'll do the following:
Start: three start strokes; 10 sprint strokes at about 40 SPM (strokes per minute)
450m: "power 10" with focus on rhythm and relaxation
800m: power 20
1,100m: tighten screws, i.e., try to pick up the pace about 1 or 2 sec. per 500m
1,250m: hang on
Ah, now there's the interesting part: "hang on." Ordinarily I'd say, "throw in the kitchen sink," "go blind," "even if you don't believe in God, now's when you see Him," etc. But on Saturday we will have exhausted ourselves on the ring dips/squats and clean-and-jerk/burpees. And not just in our lungs. We are going to be muscularly fatigued in a big way. So it's doubtful that, when we punch the gas near the end of the piece, anything will really happen. Heck, we may even have trouble with those aggressive first 10-15 strokes. Hence, "hang on" for those last 250m (25-35 strokes).
In a similar vein, because of that fatigue from the previous workouts, do not expect to be able to maintain a faster pace on Saturday's 1500 than you would on a 2K when you're fresh. In other words, if you know you can pull 8:00 for 2000m (i.e., 2:00/500m pace) when you're fresh, shoot for 6:00 (also 2:00/500m pace) on Saturday. In fact, I think I'll go slightly slower at first and then start negative splitting at about 600m into it, if I can.
As always, please let me know if you have any questions!