Let’s begin with Kamen Rider W final form, CycloneJoker Extreme Form. Double will use Gaia Tori Memory to transform by put the Tori Memory (Tori = bird) into unloaded WDriver and load the Driver along with the Tory Memory. As the name, looks like only CycloneJoker Form which can get this upgraded form.
CycloneJoker Extreme will be equiped by Cho Tashoku Hakkou Ken Prism Breaker. This weapon has four Gaia Memory slots on it plus one slot for Prism Memory. As seen in above picture Double puts Heat, Luna, Cyclone and Joker Memories into it.
Next is Accel Trial as Accel’s next form. To become this form Accel will use new Memory called Maximum Counter Trial Memory on his AccelDriver. This Gaia Memory has a digital panel and mini traffic light. I’m sure that digital panel will show the count for something like Faiz’s Axel Form. The Trial Form itself has same design but now in slim blue-colored.
W Extreme reminds me to Kamen Rider Zeronos and Accel Trial to Signalman (police robo in Go Ranger series).