How high above stove should wall protection be?

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I am about to install an older model of Hearth Craft, Spain wood burning stove in a corner of our home. Fortunately or unfortunately we have LOTS of vinyl windows. So I have read where the minimum clearance from a combustible wall is 12" and am planning on using 1/4" wall board mounted at least 1" from the wood paneling walls to protect them. As you can see from the photo, the window sills are at 18" above the 2" pavers and 1/2" cement fiberboard that I will be putting down to protect the floor. The height of the stove, with legs attached is about 33", so my question is how high do the wall boards need to be please? I'm not worried about covering up part of the window as we have 8 windows and 2 glass doors in that room!

Also what should the clearance be from combustible walls (without any shielding) to the 6" stove pipe coming out of top of stove?

We don't use the blinds, but I had to lower them in order to shield out glare and be able to get photo!!

Thanks for your input!