I am confused- do you visit during busy months, or avoid them? Your post says both that you do not have experience with them, and that you do.
I have many busy and slow season visits under my belt. There are tradeoffs to both. IMO.
Crowds usually occur in spring when the weather is ideal, so you get long park hours, which I love, and beautiful flowers/plants. Compared to other times of year, spring = spending a bigger % of my time smelling the roses. (just a tad less on rides)
It is worth noting, that Universal's gardening team also does an amazing job! Right now, Seussland has AMAZING topiaries! Most people walk right past them, but I advise all of you to stop and enjoy them. There are some especially cute ones near One Fish two Fish. They are shaped like Seuss-style fish! The gardens of Epic are also exceptional, and add a great deal to the park.