For those who have been testing out their own variants of their Spectral Duke Dragon deck, you would have realised that SDD allows you to restructure the field whenever the effect is used. So if there is space in your grade 1 slot, you might wanna consider playtesting these 2 cards, Silver Fang Witch and Blessing Owl.
Spectral Duke Dragon has a flaw whereby when the opp has a higher base VG than you, you will not be able to hit the VG unless your VG gets a trigger boost along the way. To fix this, Blessing Owl does the job. Blessing owl's effect is similar to that of Starlight Unicorn of the Royal Paladin Clan. It is able to give a +2000 boost to any other Gold Paladin on the field before being sacrificed to SDD. Its 6000 power is still decent enough to make 15k/16k power lines.
Of course, you can also go beyond the limits and give SDD another +3000 power via "Flame of Victory", making SDD a possible 15/16k base vg when attacking.
A sample grade 1 lineup would look something like this:
4 Knight of Fine Skill, Gareth
4 Jet Black Vanguard, Vortimer
3 Halo Shield Mark
3 Blessing Owl
Another card that you might wanna add (in moderation) is Silver Fang Witch. Though having a low power, it nets you an extra card before sacrificing it to SDD. However, since you can only activate the effect at the maximum of 2 times in a game, it is not recommended to play so much copies of the card. Probably at most 2 copies.