This is an old thread (back from 2017) and like 30+ replies long BUT it's got some strong tips about speech bubbles
I think with regards to balancing text, art and especially creating good spacing for all of it is to count for text from the moment you thumbnail. Finding ways to cut the fluff for lines that feel too wordy or seeing what can become an action performed by a character or just a general show not tell will help build much stronger balance between things
I know I'm constantly bringing up Sonic but the IDW comics I feel have done a really good job with the way they handle text on a page and even part with a lot of talking or lots of characters talking are well balanced
for example an interrupted monologue from issue seven
or a sort of team huddle from issue 25
course it helps to have some variation in bubble shapes to aid with tone and impact of something a character is saying and how they're saying it
also managed to find this thread on twitter with some quick digging for speech bubble tips as well (among what looks like a handful of other things that go with it but all relevant nonetheless)
https://twitter.com/h0lysarthole/status/1117494276135489536
but i feel like planning for character dialogue or other things from the earliest drawing stages possible is the best way to go and then double checking flow and readability coz if things feel crammed on the page or its looking more book than comic then it's probably gonna need some trimming down or rearranging