After sunbean nerf, day 13 in dark ages is almost impossible

I'm taking this as a personal challenge. Just played through a couple times. I lost with 4990 Sun banked. Unbelievable.
Recommendations:
If you Have Witch Hazel, use it. Pair it up with a Power Lily if you can. Turn some zombies into Toadstool and boost it to produce more Sun.
Use Hurrikale to buy yourself some time for Sunbean to refresh.
I Imitated Geavebuster (only because I couldn't Imitate Sunbean). This helped me knock out Sun graves faster.
Keep shoveling up your plants. Especially Witch Hazels if you use them. They will keep picking off the zombies that you need to ingest a Sunbean.
Magnet-Shroom is a must, now that the Sunbean nerf entails removing armor from Zombies before gaining any Sun from them.
If it comes down to it, you may need to feed more than one Sunbean to a zombie.
Other notes.. I used Cold Snapdragon. It's become my go-to anywhere besides FBC. This slows the zombies down and buys more time.

I used:
Sunbean
Gravebuster
Imitater
Power Lily
Cold Snapdragon
Hurrikale
Witch Hazel
Magnet-Shroom
In the future I will consider using Stunion or Iceberg Lettuce to stretch out my game.
Also: be ready for the lone Gargantuar to throw his Imp. They're good for Sun, too!