Tool Change

Is there already a solution to this?
What I want to do is set up a button that will let me add the height of my work piece so that when my router go to the tool change location and I get a new offset for the tool length it uses the new tool length and height of my work piece for the correct position.

like the way it is normally done in gmoccopy.

I have my touch off plate mounted on a specific location on my work surface "that is what I think I can already have accomplish with little problem"

the button and the rest I don't have a solution for at the moment. and think someone may have already doe this but I have not stubbled across it.

the way is
button cals ngc
in ngc
get the tool in spindle #5400
get the z of the mashine coordinate either #5422 of G53 or if you get G38 #5063
then from INI the ofset of the Probe to the mashine Z zero
calculate the ofset (( tool 0 is always Z 0
now use G10 L1 www.linuxcnc.org/docs/html/gcode/g-code.html#gcode:g10-l1
then reload the tool offset G43 Hx thats all

now if you go to Zero the tool shoudt be there

In a since that's the just of what I was going to do but I need a way of entering my stock height and then calculating it with the touchoff of the new tool so the new tool will be correct in relation to stock top with each change. The stock size may change with each new part. That part may have multiple tool changes and with my router set up the tool lengths will vary each time they are changed. I dont want to have to break each tool path into multiple jobs.

The tools have to be touched off every time they are changed. The height of the work piece will be calculated after the first touchoff but I have to be able to enter the stock height off the work surface. The touch plate is mounted on the work surface and since I a working with wood it's not as simple to just touch off on the top of the work piece with good accuracy without a touch plate on top of it. Or I am just missing something here.