Rear arch replacement

Hello folks, been a while since ive been on here, new site is looking good, and lets me actually log in... anyway, i started doing my bodywork, (ovlov dark grey everything, bumpers, wheels, grill, spoiler, flush boot removed, B pillars and door handles too!) and i started to scrape the scabbing off of the back arches, it was then that i decided to replace them, ive now got the panels, the welding gas, grinder blades, everything to go ahead, even the weekend off from the missus, and i just thought id come on here and ask if there is anything i need to know when i start chopping the old arches off... any help obviously massively appreciated!! :thumb:

the less of the new panel the better but cut back till you get good metal not thin scabby stuff

Some tips in this thread CLICKYME

nice one lads, should be a piece of p1 ss really, i dont have/access to a joggler so ill have to do it the hard way and butt join the new panels... spot weld 2" apart as said in that thread but let it cool, then spot weld between the 2" spots and repeat again and again until its totally sealed up... im not sure how far im going to have to go but im going to avoid going down to the sill or the bit behind the rear bumper, that looks like a mission... and theyre only pattern panels so could be a potential frikkin savage headache...