I'm glad you are having fun and getting there. I have another adventure I started last month, currently on hold, which feels very much by the seat of my pants, as I am not sure where I am going with it.
Some of the formatting I have done to make better use of the space has been very time consuming. I have kept my original spacing between the lines within the paragraphs and yes, it is pretty much similar to the spacing we have in these messages. I really would not want to shrink that and am not sure how much it would be possible to do so before it made the text less easy to read.
I agree the spacing could be useful for bigger works. I am use to the size limit being determined by word count, with the publisher doing the formatting but with the Gamebook Zine it is by number of pages and I would like to try submitting a longer adventure to it outside of this competition.