Help Removing Exhaust Spring Bolts with Rust and Corrosion

I am in the process of replacing the engine on my 2010 Prius. I have most of my old engine ready to lift out, but I am having a lot of trouble removing the spring bolts from the exhaust manifold. I live in the Midwest, and the snow and salt have really done a number on everything.

Currently, the bolts have been soaking in PB Blaster for around 15 hours, and I still can't get them to budge. I haven't been able to find any threads on Priuschat that deal specifically with this, and none of the reading materials or videos I've found online go over the best way of detaching the exhaust manifold during an engine removal, let alone one with so much corrosion. I have a bernzomatic torch, but I'm nervous about using it after applying PB Blaster. I've attached pictures of the spring bolts from both sides.

Does anyone with engine removal experience have advice for me on how to remove these spring bolts? Thank you very much!

 

I think I actually took a sideways route. Instead of removing the spring bolts from the catalytic convertor side, I removed the 5 nuts and studs that connected the exhaust to the engine block (along with the bolts on the brace). The engine is ALMOST fully disconnected and will be coming out today!

Thank you for your response. It might be something I use in a bit, when I can get a bit more leverage. Even if it's not, it's great advice and I'm glad it's out there for anyone else who might have this problem.