How i did it with pretty good luck...
Use
35 mil. film or the containers that you get when you buy 50 meal worms. 1 large worm per container. A little oatmeal.
I simple placed them into the container, then into a 5 gal fish tank (empty) and sat them on an upper level shelf. Checked on them once a week, removed the dead ones, when they did the morph from worm to larve, I removed them and place them in a clear plastic clear flat container ( butter cup size ) could hold approx 10 larve stage. I keep a watch on them and when the larve changes to a beetle i just removed it and placed it into another 5 gallon fish tank... My worms were never ovr room temp and this winter i think the are at low 60's. I have not tried morphing them this winter.
Key things.
Temp- well.... it was summer, i have Ac, I would guess room was in mid 70's
Light- I placed the larve cup inside a magazine holder so it stayed mostly dark. The bettles were in a variety of containers from dark film cannisters to clear platic ones.
So, I didnt go to any great steps and I know that they were colder than your mid 80's...
Good luck