Don´t know how I should list this, but here goes, in case anybody else is thinking of doing their own chai blends. I made my first batch and I am impressed, it turned out pretty much to my taste and much better than I thought it would.
My favorite chai so far is Mariage Frères´ Chandernagor, a mix of just four spices – cinnamon, cardamom, cloves and pepper; all balanced in a way that seems perfection to me. I tried to be inspired by that, and remembered that Chandernagor is a tea which I was dubious about because dry it smelled too strongly of cloves. I considered that a tip to add a little bit more of cloves than my nose would think OK.
the base: 50 grams of plain, strong black tea. I used some golden Pekoe tea from the Azores which I had at hand, and was probably already pretty old. It´s a pretty malty tea and I think it worked very well. Assam is probably more canonical and what I would use when I run out of this Gorreana black tea.
the spices – I used seeds of 12 green cardamom pods, half a teaspoon of ground cloves (whole cloves would be better, I would use 12 but I did not have them at hand. Ground spices will probably impart a lot more flavour than the same volume of whole spices so I went with my nose), 12 black pepper grains and then cinnamon, hard to measure or describe. I used some very sweet, very thin cinnamon bark broken in pieces with fingers (very thin!) or knife tip, and a smidgeon of ground cinnamon just because. I pounded it a bit in a pestle till broken up. I mixed the spices with the tea, put it in a sealed pot and waited about a few days, shaking it now and then.
Brew it chai style, a generous helping on simmering milk with a bit of brown sugar, and it was NOT BAD at all. Maybe not quite the best chai ever but much more to my taste than a few other chai mixes I have tried so far. So don´t be afraid to try your own chai mixes and be pretty conservative about the ingredients.