Blazinjones, I've never done autos. Here is a link to an old journal here from a guy that was pretty dialed in as far as making fem beans with auto plants.
How to Make Feminized Seeds With Colloidal Silver - Sponsored by Intelligent-Gro LED
To provide my input on sacs with none to very little pollen I had this problem my first few times using CS. I only make fem pollen using clones and very small clones at that. Usually only 3-5 inches when I take the cutting. Me personally I don't want to take the risk with my health spraying any part of a plant I plan to harvest and consume. I think using CS for too long and to strong of a solution also plays a big part along with not letting the clone get well rooted first. My first attempt I was spraying the entire clone every day for weeks and used around 60 - 80 ppm. The leaves looked sick but it produced a ton of sacs. None ever opened on there own. When I force them open some had very little pollen and some none. I even had a clone that none of the balls had pollen in it. I thought maybe I picked them too early so I let them sit longer and some sacs were falling off the plant without opening on their own. If there was pollen it was usable however and produced fem seeds when pollinating female plants. After 3 or 4 attempts with same results on various strains I changed things up my last run early last year. This is what I did that worked successfully with clones on a BubbleGum strain.
1. Let the clone get well rooted. Leaves should be perky and displaying growth. For me that's around 10-12 days.
2.Sprayed entire plant with CS solution (~50 ppm) day before flip. I spray once a day right at lights on or within 1-2 hours.
3.Next day I spray entire plant again.
4.On the 3rd day and beyond I only do tiny little sprays only at the internodes where new growth is. I don't spray any of the fans. Just the new growth areas. And it only takes very little, tiny squirts at each node. My thought here is to keep plant healthy by doing this. Again, I only sprayed once a day.
5.I keep repeating step 4 until the first sign of balls. Once I see that I stop spraying. Last run that was a total of 2 weeks spraying once a day. Thought process being once you see balls the plant has converted. No need to spray anymore. The clone ended up with a ton of ball sacs that opened on their own full of pollen.
This worked for me using *clones* purely to make fem pollen. I've never done big girls or partially sprayed plants. My clones end up looking like males with very little pistils. You wouldn't be able to tell they were female without seeing the mother plant full of buds. The CS I use is the same as what's been posted here before and is about 3 years old. I still have half of that bottle left.
Currenlty I'm trying to create fem pollen with a Serious 6 plant. Hoping for the same success using the steps above.
Best of luck to everyone giving a crack at making fem beans. May you generate many balls full of yellow powder