I actually abandoned writing out scripts ahead of time a looooong time ago. It's a big advantage of being both writer and artist, I do much better designing the flow of my story visually, and I'm able to give myself a general jist of what the characters are going to say. I find it's a lot easier to write the specifics of dialogue in after I know A: the facial expressions and body language that are going to accompany said dialogue, and B: the amount of space I have to work with fitting the bubbles comfortably in with the artwork.
I have been told I'm crazy for doing this, and it definitely comes with some drawbacks of its own, just like any method, but it's WAY more comfortable for me to work with.
If you're just a writer working with an artist, then my best advice is to trust the hell out of your artist.
If you can't figure out how to represent something visually, do the best you can and ask the artist to do their best to fill in the gaps. If your artist decides 1 panel needs to be 2 panels or 2 panels need to be 1, trust them and let them make those changes.
Your job as the writer is to determine pacing, themes, narrative, characters, and dialogue. The artist's job is to handle composition and flow. Often those things will have some overlap, so drawing the line between them can be a little messy, but it's okay if the script isn't represented 100% perfectly once it translates over to comic pages; sometimes fixes need to be made on the fly based on specific unforeseen details, and that's totally okay.
Especially if you're both writer and artist, but even if you're just writer, the Script is, to some degree, a guide, not an excact 1:1 immutable law.