see what the heavy strings do for you first. No piont paying a tech if the strings fix it. It won't hurt anything to try them first. 13s would be considered mediums for
slide so they may not pull the strings up enough. I played 13s on my non slide guitars for years and found that the high E string took a light touch not to fret out when using a slide. I play dropped d so I don't know if open E tuning would put more tension than that on your strings. I use 16s for slide on electric and 13s for accustic.