Instagram has really weird limit with their DMs. I have been DMing almost every day since July and after the Instagram "Purge" about a month ago, DMs have been very inconsistent. There are days where all of my accounts have hit 120+ and some days where they all get stopped around 30-60. To be honest, the best advice I have for you is the following:
- Change your pictures on a daily/weekly basis.
- Change your text on a daily/weekly basis.
- Have a long delay limit. My best success has been 100-250 seconds between each sending.
- Give them rest days every now and then to avoid limits and bans.
- Keep all your other account actions to a minimum. Avoid doing any other excessive commenting, liking, following or unfollowing while you are DMing 100+ a day.
Hope this helps,
Fenchel