Good to hear that you kept your conditioning up. I'd simply add more as you feel able. It sounds like you have enough experience to know what you're ready for and when.
I vary it. I don't ever throw hard enough to strain myself, which is a danger if you fire hard into thin air. If I go fast, I tend to stop just short of full extension, if I slow the pace, I try to focus on perfect technique and crispness.
A good test, in my view, of whether you are as fit as you think you are is to shadowbox for 30 minutes. That means moving around up on your toes, pivoting, slipping etc, as well as shooting for a high output of punches. You ought to be able to do this nonstop for 30 minutes without any real fatigue in any of your muscles. It should feel like a warmup. If you're out of breath or aching in your muscles, you probably aren't in condition to do 3x3 minute rounds of a stand up striking art.