Tennants in common question

Hello, my wife and I are buying our first BTL property in joint names but I want to maximise my wifes income tax allowance and have her the majority share. Our solicitor has suggested that rather then have to take out a declaration of trust afterwards and then complete the Form 17 with HMRC he decalres this up front on the deeds.

Does anyone see any pitfalls with this and also how easy would it be to transfer to 50/50 at a later date to maxime our joint CGT allowance on any profit from the sale.

Thanks for any advice

Pete