I noticed that Mann Lake and Dadant both advise that only experienced beeks use small cell foundation. Why is this?
Some things are a mystery.
Like why ask about 4.9 foundation in the "natural and organic methods" beekeeping forum? There is nothing natural about it. And it don't make your hive organic.
Natural to me is at least letting the bees draw comb without a pattern (foundationless systems) and not forcing them on large cell, or small cell.
I use both LC and SC. But I think folks need to keep it in perspective, and realize there is nothing natural about forcing bees on 4.9 full sheets of foundation.
Suppliers don't want to deal with the issue of having folks buy SC foundation, then having them call back after the bees do not follow the pattern. Many times, they do not automatically draw the 4.9 foundation. they make their own comb over the foundation. Many times, this comb is drone, and all different size comb, based on need, time of the year, etc.
It's not like they utilize some SC this year, then some more next year, until they have all SC comb. Having them draw bigger comb, or even drone comb over the SC foundation, does little to regress bees. There is more to it than that. Simply having bees draw what they want over the SC foundation, then pulling it out and doing it again next year, then doing it again, then after three years thinking your bees will be regressed, will not be what you thought. If they keep drawing comb over top the SC pattern and favoring their own, it does little to regress bees.
So constant filtering in SC to the right location, at the right time of the year, keeping honey out of the area, all makes huge impacts. You can burn through many SC sheets of foundation trying to get smaller bees. Been there, done that. Even with SC foundation, bees make what they want.
Myself, I favor natural foundationless systems.