You might as well give up on modifying your old trans skid, because you want a skid that will protect your oil pan as well. My buddy Vegrent helped me modify---I mean did all the fab work--- a old warn skid plate I already had. It looks just like a Skid Row skid when we were done.
You can measure my skid or get the measurements from skid row, or UCF skid plate and have it cut out at local metal shop and get someone to weld in brackets and be done for a lot cheaper price.