Got an unexpected clutch. Trying maternal incubation. Any tips to a first timer?

[Alicia]

I did MI with an unplanned retained sperm clutch a few years ago. Other than the loss of one full term baby that just never pipped, it went quite well. A couple things -

First, 86-88 is fine for eggs. You will get cooler temps and more fluctuations with an MI clutch.

The actual temperature under the egg mass may be higher. If it's too high, this, too, can kill eggs. If you're tempted to dial it up, refrain. Ball Pythons don't appear able to raise the temperature of their clutches like other pythons, by the can lower temps that are too warm by opening their coils, or even leaving the clutch for a bit.

75-80% humidity is what you want with MI. The mother regulates humidity of the clutch itself by opening and closing her coils. If things are too wet, you risk killing the eggs and the mother may suffer skin damage. 90% or higher is what we shoot for in artificial incubation. I'll have to dig up my notes, but it seems like Lady Dahlia's cage hoovered around 72-75% humidity for the whole of her MI. If your female is in her hide with her clutch, I can almost guarantee you, humidity is higher than 80%

One of the things you really do want to avoid is getting those eggs wet, or allowing them to sit on a wet surface. This is a killer for eggs. If feel you need to add more humidity, mist the opposite side of the cage, not on or around the mother.

A good material for a nesting female is lightly damp sphagnum moss. Soak it, wring it out until it is almost dry, and put it around the outside of her hide box. Try not to mess with her too much. The moss is great for mild humidity, as well as being antimicrobial.

Other than that, the main thing I can think of is, try not to bother her too much.
Hopefully any of that helped, and best of luck with the clutch!!