so i actually did some work, that's why i took so long to post.
i found a way to use a z axis and not change the direction of where the xy table would look (i don't know if u understood this bit)
i hung a car's jack (or jag: don't know how to spell it) at the bottom of the table and when i would need to change the height, i can first open the nut at the rear of the table then change the height using the jack and then tight the nut again for security.
on the other hand, i am still not decided what xy table i am going to buy: i saw this
link what do you think??
do you have other sources??
thank you
another thing that i modified before will start milling was the outlets positions. because i had to increase the size of the input, the 3 barbs did not fit near each other
so i had to remodify the drawing again