I don’t think the length of your post affects how it relays, but I could be wrong. On Nostr, your note is broadcast to the network, but there’s no algorithm pushing it into people’s feeds. It appears only to your followers, and from there it can spread if they repost it. Reposts from people with larger followings will have the biggest impact on reach.
You can also repost your own note at different hours to catch followers in other time zones or those whose feeds are crowded. Using popular hashtags may help as well, since some people follow or browse them.
If your note gathers around 30–50 likes, reposts, and/or comments, it may show up on Nostr’s Trending, which gives you another boost for about 24 hours.
Bottom line: reposting is your best tool for reaching more people. After zapping others, it’s also the best way to boost their message. Likes are largely a vanity metric here, unlike everywhere else on social media.