steeping Caramunich and Caravienna

I wonder if you could help out a kits and bits brewer by answering this question? About a year ago I started steeping specialty grains and adding them to my kits, to perk them up. I started out with crystal 30L, 60L, and 120L (but have also used roasted barley, black patent, and chocolate malt). Usually my crystal additions are between 100-300gm/23 liter batch (= 3.5-10.5oz/6 US gallons). I have been thinking about trying Caramunich or Caravienna, but in the amounts I am using, and the method I am using (steeping) would I notice much difference between crystal 60L and Caramunich, a bit of toasty-ness perhaps, or malty-ness, or nutty-ness, any of which would be welcome? Or between crystal 30L and Caravienna? Some people say Cara-malts are less sweet than crystal malts; would the entire effect be too subtle to make it worthwhile? Would I have to use more to get both sweetness and whatever other quality they may bring to the table? Is it worth the extra money? The brand of Cara my LHBS carries is Malteries Franco-Belges (MFB). Not sure what brand the crystal is, might be Briess. Thank you for your response. Oh, my LHBS prepackages everything, so I can't chew the grains in the store to get a sneak preview.

PS Please don't suggest going partial mash or all grain. Much appreciated.