Hi Billycat,
Assuming you use the base for 4 portions, each curry will contain half a green chilli and half a tsp of chilli powder. I dont imagine that could make anything too hot but as I have only used this for Madras I can't accurately comment.
Regarding the yoghurt, to quote JerryM's feedback he kindly emailed me:
yogurt - something gave the base a taste i'd not come across. i can only think it was the yogurt. i liked the taste and would probably go up significantly to prove or otherwise. too much would not be a good either so maybe say 4 tbsp. i would defo keep it in and will probably try it in my base.
PaulP - I agree there is the same amount of work involved, you just dont have to boil this one for 2 hours before it is ready. I can cook a Madras from scratch within 45 minutes. If you have a Saturday afternoon free to make a big batch of base then go for it, if you want a quick Wednesday night curry after work (assuming you dont have base in the freezer) then this is for you.
This recipe and method isn't here to replace what people already do, it just offers a quick alternative and tastes almost as good as BIR quality. For some (like me), it might be exactly what they are looking for. If you have all the ingredients then knock one up this evening and let me know your thoughts. Everyone who has tried it so far has been surprised by the results.