It is YOUR rocket, so set your own goals.
Food for thought, however.
You aren’t going to win any altitude records, so I am guessing you are going for show, which is great!
This rocket would be cool even if it was just a single stage. Cool rockets don’t NEED to go very high, in fact, I don’t think getting them much over say 500 feet makes them any cooler, just harder to recover.
Going for single booster to multiple sustainers itself is (at least to me) super cool. The Estes MIRV was a cool concept and a great LOOKING rocket, unfortunately poorly executed mainly as booster severely underpowered.
I wonder if they will re-release it if/when they come up with a C5-0.
But in any case, the cool factor is diminished the higher the staging altitude. You WANT this to stage low, say 100 to 200 feet for at least two reasons, possibly 3.
1. You want to see (and those at your launch will want to see) this puppy stage. That will be clearly visible up to 300 feet. At 1000 feet it’s gonna be a little bit like the Saturn Jupiter conjunction, seen with the naked eye it was okay, seen through binocs or a telescope was more impressive.
2. You probably want to launch this more than once. I went to NSL hosted by ROC (kudos to them, BTW, was great) and they were nice enough to entertain us LPR mortals. I had a single stage intentional CATO recovery I built (google Estes CATO or see here
https://www.rocketryforum.com/threads/estes-cato-clone.126220/) that deployed at around 150 feet on flat playa and I STILL couldn’t find all the pieces, the smallest of which was about 10 inches in decorated with colored Mylar tape. There is a strong possibility that your multiple sustainers may deploy in a StarBurst maneuver, which will look cool but imagine three sustainers going in three different directions before deploying....... and then trying to track them. BTW, STRONGLY recommend you go with minimum newton motor for boosters. If your staging works, they are already at stable velocity when they stage, consider even DOWNSIZING a motor diameter with an adapter (like 18mm to 13mm 1/4A-3T. At least for first flight.)
Possibly 3. If you have tilt and altitude lockouts on your electronics you PROBABLY don’t need this. But
@JimJarvis50 aside, the higher your booster goes, the more likely it will be something less than vertical at staging. Non-vertical staging, particularly if it is 90 degrees or more off vertical, is generally considered poor form, it is NOT the entertainment you want to see in person, nor (if your name is mentioned) do you want to see it later on YouTube. This is also why especially for first flights you should use small sustainer motors, if the light off vertical they won’t go as far and won’t have as much energy if there is fecal turbine interaction.