Need advice on sip and puff wheelchairs

I am new to the power chair world. A little background....

I have had FND for years. Long story short, it took away the function in my legs a year ago, so I used a manual wheelchair for the last year. Two months ago, it paralyzed me from the chin down. I cannot move anything from my chin down, including my neck. I have no movement except for my face. Therapy has been trying to work with me in the last two weeks, and are finally helping me purchase a power chair. I trialed a sip and puff, and I want to know others' opinions on it.

I also would love to know if anyone has suggestions on splinting for contractures. Because I wasn't able to start therapy right when my body became paralyzed, my arms, hands, and legs are starting to contract. My hands are pretty bad, and so are my feet. Any suggestions would be really helpful. Thank you.