SDL 2 SDL_Texture scaling and rotating

I am writing a find a word mobile app.

To create the strike out effect I am using 3 textures.
image
image
image

This is so the ends won’t look funny when scaled. I have tried to scale the middle image but it gets offset to some location, that I cannot figure out how to get it to render in the correct location.
So I changed to rendering multiple copies of the middle texture to fill in the space (see image below for the result). This works, but when the puzzle is nearly complete there is a noticeable frame rate drop.

image

Can some one either tell me how to get a single middle image to scale and rotate so that is is correctly positioned; or is it possible to copy from an SDL_Texture with SDL_TEXTUREACCESS_TARGET access to an SDL_Texture with SDL_TEXTUREACCESS_STREAMING access. As I can copy the final drawn image to an image with SDL_TEXTUREACCESS_TARGET, I would like to then render it back to the original image and this would solve the speed problem.

Thanks