Instead of 3 thunder dragons use 3 BEWD and change the 2 Twin-headed thunder dragons for the 2 Blue eyes ultimate dragons.
Although maybe 3 thunder dragons would be for the best since your objective is to fusion as soon as possible and thunder dragon's effect is perfect for that.
Would that work? you have a max of 3 BEWD per deck. And you Cannot Summon BEUD using 1 BEWD and 2 alternative fusion materials(i've tried). You need a minimum of 2 BEWD + 1 alt to fusion a BEUD. Therefore, you actually cannot fusion summon 2 Ultimate dragons. It's useless to have 2 BEUD in your deck unless you intend to Cyberstein/summoner of illusions it.
Really? in that case ill have to throw in summoner until i pick up mereor b. I've only been opening ultimate since it will be removed. just 1 more kuriboh then i can start neo !