I'm using platform pedals now, and just got some BIG sorel boots, with room for three pairs of wool socks and I can still wiggle my toes. I can keep my feet warm for an hour and a half. It is the last hour that kills me. I tried some new chemical warmers, and they seemed to work better. My "Little Hotties" give out after an hour and a half; these "Hot Spot" warmers were still going strong hours after my ride. I also got some aerogel insoles, and they seemed to help. I survived a 3 hr ride at -14°F, so I guess I shouldn't complain.

The problem is not lack of insulation, the problem is pressure on my feet squeezing all the blood out. I know I should "spin" more, but have you tried spinning while riding Sorels? The boots alone weigh 5 or 6 pounds. If I get off my bike and walk it for a half mile, my toes warm up, even though my heart rate goes way down. But stopping and walking makes my commute even longer . . .and I might even start to get Angry at Winter!

Next thing I'm going to try is some energy bars made of that Purina Ape chow. Ape Chow . . . mmmmmm. Makes me warm just thinking about it.

Layer with some wool felt liners instead of 3 wool socks to keep the blood flowing inside your feet. One wool socks with 1 or 2 layers of wool felt liners.
If it was me I would focus on having some room to let the blood flowing and would focus on adding several insoles (wool, reflective aluminum, aerogel...) + the plastic bag socks (vapor barrier)
In my case for long rides i wear vapor barrier socks in my mukluks so that the length of the ride has nearly no impact on my feet comfort. I did a 12hr ride the other day at 0F with one 1/2hr part walking and pushing the bike in 3 feet deep snow and my feet were comfy all day long.

I have large( size 15 ) feet. Right now I'm using NEOS overshoes, a liner with some support, and my inserts from my sorrels with thick and thin sock. Works great. bulky but not heavy and very warm. 3 hours at 14 F.