Just as short post, so I don't forget this myself haha.
I don't think it is immediately obvious, but the starting Vanguard for Jewel Knights, Dreaming Jewel Knight Tiffany, actually gives more power to the field with her skill than if she boosts (3k to 2 units for a total of 6k vs boosting 1 unit for 5k). Down side being the loss of 1 unit and the skill only lasts for a turn. Another thing to consider is giving yourself additional soul and being able to call Tiffany with Sybil or Salome, which essentially turns their skills into Counter Blast 2 to add 1 card to soul and give 2 Jewel Knights +3k power.
This is useful if you want to play Soul Saviour Dragon, which actually helps out a lot in ending games. Also useful to increase the number of Jewel Knights in the deck, since there aren't enough Jewel Knights at the moment to play a full deck of Jewel Knights with normal grade distributions.
Playing more Grade 0s also has other upsides. 5k boosts actually aren't bad at all, as they force your opponent to drop additional 5k guard when played right and Tiffany can leave the field easily with her skill. Also more 10k shields in the deck overall.
Personally, I consider playing 1 additional Tiffany, but I don't currently play Soul Saviour Dragon in my Jewel Knight deck. Trying a different build for a while and I won't change it any time soon I think. Playing 3 Dreaming Jewel Knight Tiffany, might be pushing it, but I think it's worth considering if using Soul Saviour Dragon's skill is a big concern. Since Tiffany can be called through skills and you only need 1 additional one to trigger SSD, Margal is not necessary and the deck can play a maximum amount of Jewel Knights.
Just some food for thought, if I do test it I'll probably update this post with my findings. If anyone else reads this and tries it, please do post in the comments how it went! :]
