Since it's tweed, I'd be less worried about shortening the sleeve since the texture is more forgiving than wool. Check with your trusted tailor.
Also, how do you like the tweed style? I dont own any yet, but have tried a dress in tweed. I feel like it's got more stretch than the classic wool blazer.
Yes, I have an alterations specialist who is amazing. I will check with her.
I personally prefer tweed to wool. I love how classic it looks in the collarless style. Plus, I find wool incredibly itchy and tweed more comfortable to wear