are you replacing the whole 1/4 panel? or just the lower halfs?
the lower panel is pretty easy to swap!
the complete panel is a big job to say the least.
i have done whole panels and the way i did it (my way) was to leave about a 1/2" all the way around the perimeter on the panel i was removing and then i layed the new one in place and matched up the edges and tack welded it all the way around and then grinded the welds down and smeared mud!
i just used a die grinder cutting wheel to make the cuts! be careful not to cut thru the inner fender or you will have to fix it too!
the panel is sandwiched there are two panels there!
hope this helps?