I'd get one of the MDH spice mixes and mix it into coconut oil to help preserve the flavor and help liberate the spices. I agree that Patak's has a lot of veg oil in things like the tikka paste. If you can't get MDH (or another spice mix brand) locally (I get them at an Indian grocer) then Amazon has them:
I like Sharwood's stuff, too, but a jar of sauce doesn't keep as well as spices in coconut oil - the whole jar has to be used pretty quickly. I'd make it strong like the tikka paste and just use a big heaping tablespoon of it with the meat/vegetables and thin with coconut milk.
I've been using the jar stuff but sometimes the big batch is too much. I think I'd make Indian in little batches more often if I got around to making a paste, so I need to heed my own advice here. The spices in powdered form are a little hard to use and take a while to infuse. I should really do this myself, as I am trying to get more turmeric and other spices into my diet more regularly. I may mix some up later, and bump up the turmeric into whatever Indian mix I have in the cupboard. As much as I am great at cooking and making things from scratch, Indian is much harder to get just right!
Ok, I made this earlier today by mixing two kinds of MDH spice mixes I have and some amchur (mango) powder, along with extra turmeric, paprika and dried parsley. I warmed coconut oil just enough to liquefy it and mixed it with the dried spices. Since I wasn't wild about how it settled out when it solidified, I added some olive oil so it would be easier to mix. It's not a pretty red color like Patak's, but it's tasty and should be convenient to use. I don't think it will need refrigeration, but since I added the mango powder (which is very tart, and perhaps a good sub for tamarind) I'm not as sure about that, so I will probably refrigerate it.
A note about MDH... there is added salt in the mixes FWIW. It's also made in India and much hotter than any of the Patak's or Sharwood's sauces/pastes I have used, so bear that in mind.
My only concern now is that I haven't used any of the MDH spices much since I was diagnosed with celiac disease last year, and I'm somewhat sure I've been glutened by cross contamination from cheap Indian spices before, probably from making flour on the line before grinding spices on the same machinery (and this is not uncommon for people with celiac disease). I didn't have any problems after my last visit to an Indian restaurant, so I am hopeful. Anyway, it's probably not enough gluten to bother someone who isn't sensitive, but in case anyone with celiac disease is reading this, I figure it's worth noting that Indian spices can be suspect for cross contamination.