gantry mode issue

i have got it to work now, 

Hello friends, I'm building a machine like this now.  I'm using version 2.9 with Gmoccapy created in pnconfig (XYYZ).  I tested the immediate home and it works perfectly, and I tested it with limit switches (not sensors) putting the sequence from home to Y at -2 for both joints and the machine does not move before home, it generates a message.  Now I have two questions too, one how do I use a limit switch for each joint?  (Because I tested it and I couldn't make it synchronize, the first joint that arrives already wants to come back and the second one going is still due to mechanical effort and generates an over load alarm in the drives) (my next reference sequence: the machine moves towards the key in programmed rapid advance, returns about 5mm and advances slowly until it touches the key).  My machine uses linear guides and ball screws, very rigid machine and any wrong movement of the joints generates alarm.  Another problem with precision in the machine and as it has 2 meters on the X axis, any wrong movement it is far outside the X-Y square.  The second question, is there any way to adjust the offset (similar to backlash) of the two separate Y joints to fine-tune the squareness between the X-Y axes?