I also made my own. USed ideas from OEMY's site. Just search this forum for that reference.
I went with Cat 1 from Tractor Supply. CAT 1 was the right length for my F53, which I believe is the critical consideration. I don't think the center link itself is having to work very hard. The critical part to me is the differential bolts. Change the short cheapee OE bolts that will secure the bracket to the suspension to longer Grade 8 (gold color). TS also sells those. Do use red Locktite on all the threads. I have about 3 dozen other custom DIY changes to my RV. I value that one improvement the most and it requires just about the least worries in the upkeep department. Indispensable if traveling on the windy plains or in heavy traffic with zooming semi's.