That link has pictures and how to make a tool that makes it easier to do.
I would just flare them and save the 5-700 bucks after having the glass installed(depending on type and who installs it). You can keep your bed if you use glass, but if you are using glass in the rear you are probably already missing half the bed floor anyway. THe easiest way to do that is to drill all the spot welds off the fender skin and the skin will come off allowing you to bolt up the glass.
Flaring the fenders cost less than $20 to do it yourself or $150 at most shops.
I have a question requarding glass bedsides, i just got some for my 92 ranger 4x, and i had thought that the method of mounting them while still retaining the bed was to cut the sides off with a sawsall and leave the bed rail for structural support, or would it be better to just drill the spot welds? Any info would be helpful, also maybe a picture or two of it being done would be greatly appreciated. Thanks in advance.
i don't have any pics of while i was doing it, but i did my own bedsides on my toy. took like 2 days. drilled out the spot welds with a special drill bit made just for that. also liberal use of the sawzall, to make things go quicker. left in the top rail and all the edges/tail light bucket areas. it was a lot of work, but damn those bedsides look cool....if you've got any more detailed or specific questions, i'll be happy to help, if i can.
it's specially built to remove only the spot welded area, as long as you don't push all the way thru everything with the drill. about 8 bucks a piece-i ended up going thru 2 of 'em. got them at a tool store, home depot didn't have them. i didn't remove the rail, just all the stuff around it. left in the front edge of the bed for support, and the tail light area.