(Most tokens don't have a mana cost unless they're copying something else.) If the copied token is copying something else, then the new token enters the battlefield as whatever that token copied
Choose a commander you enjoy, define a clear strategy, add 7-10 win conditions, add the core components (draw, ramp, removal), build a 36-38 land mana base with color fixing, then playtest and tune the ratio
Also, its a great way to build a backup Brudiclad if an opponent tries to kill it before you go to your attack step
If you were just finding a land the Impulse is likely just as good
2 Scavenger Regent A Plague On Nondragons Perhaps the best Dragon and Omen combo is on Scavenger Regent and Exude Toxin, an extremely versatile duo that can be a board wipe if you need it or a threat in the air