I don't really see this as an either/or situation, because not only is it the EIC that is responsible for expansion into India, but as long as America remains loyal the colonies themselves will provide more than enough manpower to expand Westward, and I don't think the British will have to really "concentrate" too much there either.
If Britain goes after India and holds on to America, I don't think her colonies on the subcontinent will be any smaller, but British North America will probably not expand to the same size as OTL's USA(excluding Canada, of course). Although the Brits may conquer Louisiana at some point, the French will never sell it to them. British-American expansion Westward will probably be slower due to the fact that Americans may want to try their luck in other parts of the Empire, and a non-independent America will also have serious butterflies on immigration(I imagine there will be less of it). I'm not saying the border will stay at the Mississippi, but we shouldn't expect an Anglo-American Texas, Southwest, or California, though Oregon is still pretty likely.
India though? India will be fine. And by fine I mean British
If Britain goes after India and holds on to America, I don't think her colonies on the subcontinent will be any smaller, but British North America will probably not expand to the same size as OTL's USA(excluding Canada, of course). Although the Brits may conquer Louisiana at some point, the French will never sell it to them. British-American expansion Westward will probably be slower due to the fact that Americans may want to try their luck in other parts of the Empire, and a non-independent America will also have serious butterflies on immigration(I imagine there will be less of it). I'm not saying the border will stay at the Mississippi, but we shouldn't expect an Anglo-American Texas, Southwest, or California, though Oregon is still pretty likely.
India though? India will be fine. And by fine I mean British