Hi astrid1000,
I’m no flour expert so not properly qualified to answer your query, can only give my opinion based on experience. There is a bewildering array of flours to choose from these days, and highly priced. I don’t want to load up my cupboards with too many of them and over time I’ve discovered a few recipes that I do make again & again so it’s worth me buying the relevant flours.
Coconut flour (and oil) – got to be honest, not my favourite cooking ingredient! I love the coconut aroma but you’ve got to get the liquids right for an acceptable result. I think coconut’s big plus is the triglycerides, supposed to help in weight loss – I’m sure someone with more knowledge than me will explain better! 🙂
Chickpea flour – you need to study the nutrition info on the bag – one brand I bought was actually 20% chickpea and 80% lentils and the carb content was high. I found a Tesco own-brand bag of gram flour which seemed to be 100% chickpea and the carb content was considerably lower. There was no discernible difference in the colour/flavour of the two flours. But the Tesco gram flour was more expensive for a bag half the size of the other brand! I like to make the cracker recipe posted in the Recipe section.
Spelt & rye flours – I use these to make the bread recipe from the book. I’ve used spelt to make seedy crackers.
The main thing I consider is whether the flours work well for the recipes I want to make. For me, any perceived health benefits are a plus. Taste comes first – if I don’t like the end result then it’s not much benefit healthwise since I won’t eat it again.
As for your query about pizza – I’ve tried alternative bases (I never warmed to the idea of a cauliflower base), the best I managed was one using chickpea flour but it was a DIY recipe and I wasn’t that impressed. Frankly, I can exist quite happily without making a fake pizza – I incline towards having a real one, as you say, as a treat.
Overall, if trying to reduce carb intake, it’s probably best to use flour (whatever variety) only occasionally.
Not sure any of the above gives you the specific info you were asking for, but hope you got something useful from it!