Razor,
for defo keep at it - well worth it. any questions just ask (i think everything is in the link i added earlier).
for info the proportions i use are (based on 1/3 of the original recipe): onion 550-600g, 12 off garlic cloves, veg oil 50ml, 4" stick cinnamon, tandoori masala 1 tbsp, tom puree 1 tbsp.
to make the ashoka version i then add: 4 off bay, turmeric 1 tbsp, salt 7.5ml, chopped tin toms 120ml, deggi 7.5ml.
nb i've stopped adding cumin just recently.