I remodeled a bathroom and decided to keep the existing ceramic floor tiles,as they were in great shape grout and all. I would like to install a marble threshold. Right now, the carpet from the short hall way butts up against the tiles edge that runs just a little past the halfway point of the width of the bottom of the door jamb. At this point would it be advisable to cut back the tile difference with a roto zip..? would this do it... clean cut,won't crack or break other tiles from the vibrations etc.? making a recessed area for the marble threshold.Or, would the done in less than 10 minutes job work by just cutting the threshold to length,notch out the necessary door stop on either side of the door jamb and adhere the threshold to the existing tile? The threshold heights i can get are 3/8", 5/8" or 3/4" all 2" wide. If this helps any... The 3/8" height leaves a gap from the top of the threshold to the bottom of the door @3/4", the 5/8" threshold has a door to threshold gap of @1/2", the 3/4" has a gap of @ 1/4". Considerations i have had. Would the 5/8" or the 3/4" threshold be to high and create a possible trip and fall or almost fall. Thank you, for any professional advice or any others input on this!