Perlite

100% you should be adding up to 30% perlite to help drainage and aerating of the soil. It does not have to be perlite you could use other inert light weight materials but perlite is a growing standard in many mixes. Good Luck!

Hello yes you can add some perlite but like said 100 % coco is good. Perlite will bring more aeration but also more retention of water. Now it's up to you. Bye

coco holds 2/3rds the volume of soil. soil suggests 50/50. coco is proportional to water volume capabilities at 70/30. (67/33, technically, but being precise here isn't a huge deal. doesnt mean less is a poblem, just that it's not as optimal for root growth and plant growth. all other things the same, you will get faster growth with 70/30 vs 100% coco. how much faster? is it a relevant difference? no idea.

No need to add any. Coco is very airy and will give your roots enough breathing without it. Happy Growing

Honestly perlite does little to help with aeration with coco in the same way it does soil. I’ve grown extensively with each - 100% coco and 70/30 with perlite. 100% coco is very aerated already

If you planning to change pot then you could add 25% Perlite or buy pre mix coco 75/25 ratio. Its best to not tranplant autos as mention below but if you do it, do it in dark to reduce stress not sure if that really help but Im doing it and when I transaplant I never had any major issues

It's too late to be asking this question! You've already got your autoflower growing and transplanting it is not a good thing to do as they don't take high stress which transplanting is. But yes, the roots need to be able to access a lot of oxygen and perlite is a perfect vehicle for that. You can try adding 1-2tsp 3% hydrogen peroxide (H2O2) to your water/nute regime as this will help bring oxygen to the roots. Good luck!

Yes, It will give your plants the best balance of aeration and water retention possible. I would go with 70% coco to 30% perlite.