our pediatrician gave us the go ahead at 7 months. however, i didn't know there was a specific age so i'd started them just before that.
i don't know how you'd go about mushing it yourself, i bought the jars. i read the ingredients on the jars though and it seems like you could put meat in the food processor with some water and tomato paste (maybe other veggies too, those 2 things would just make it "soupier"). i don't know about that for sure though since i've never made baby food on my own.
i know they sell beef, chicken, turkey, ham, and veal. they sell them as "dinners", like turkey rice dinner or chicken noodle. we actually skipped the stage 2 and went right for the 3, since finn likes texture and stage 3 dinners are chunky.
as for spices, i don't know though i'd stay away from salt. finn mostly eats our food at dinner, i don't use a lot of spices (just pepper usually), but he's had spanish rice and jalapeno chicken sausage. these aren't crazy spicy but the rice is pretty hot, he doesn't seem to mind though and they've never bothered his stomach.
have fun! give us an update when reese tries them! finn *hated* the jarred beef dinners.