I think the weights on the Q-jet As and Bs should be heeded. I started out trying to fly models that flew well on Estes B6-4 but were too heavy for the Qjet B4-4.
There is a mistake in The Cs max weight recommendation since the C12-4 and C12-6 are both listed at 113 g. 200 would probably be a good number for C12-4. The C18 uses the same flawed recommendation for 4s and 6s. The C18 and D20s should probably also be higher since they have double the initial thrust.

Beyond that, the delays for the 4 sec are a full four or more. The C5-3 is the exception but the delays for Estes are usually shorter than listed.

As long as it’s low enough to be safe.