You may not have to.....Confusedcuda just had the shop my fatty is at do the conversion.
It looks awesome. You should ask him to post some pics....so nice that he is going ahead with the back one.
The only issues are very small thin gaps below the trim where the bodywork wont match exactly to the trim...at least on his car. But they are so small and the dramatic difference the CHROME (as in polished SS) trim makes VS crappy plastic.
The trim itself covered the flaws on the edges you speak of.
USE ONLY STEEL PRODUCTS CO GASKET!!!
I am redoing mine because I bought the cheaper gasket...year one, lamesonz,egay etc....they are all the same. STEEL PRODUCTS manufactures there own and there is a HUGE difference in the way they fit.
I wasted money the first time so learn from me.