I spent all day looking on the net for answers, that is the best I can find. I tried to do a mock up off that relay shown but my solder gun is acting like an *******. I did find an LED combo park/turn bulb in the garage from my GMT400. I did confirm that it will not work off a stock flasher unit. Not enough "drain" to activate it. I got to get Old77 in here, he added LED's to his newer Burb, but I think it was taillights. He may not have dealt with the alternating flash issue, he may know who has an answer.
That diagram pic from that site must have some kind of copywrite program on it. When I try to download it I get a fuggin sex spam, and when I repost here it is very hard to read.