Once the green bar finished and Minecraft started to launch, it crashed.

I couldn't get the full log but here is the most I could get:
https://pastebin.com/CUphLebZ
I used both of your versions and they both didn't work (most likely same error)

Using this with OptiForge
I would really love to see this work!

Thanks!

It works well for me with Forge-1.15.2-31.1.17, OptiFine_1.15.2_HD_U_G1_pre9 and OptiForge-1.1.0.
Can you provide your modlist or .minecraft/logs/debug.log?

https://pastebin.com/R3Pt3iSb
theres my debug log, trying your versions of optifine and forge, edit later

edit: i tried your versions and my game just crashes when i launch forge

Ohhhh, I didn't catch that you had to drag the actual optifine jar in the mods folder as well. You should maybe clarify that in the wiki.

Thanks for this amazing mod!