I would use a local rigger and have him get the parts. Anyone with a swage machine can make these. Provide the rigger the Rigrite link so parts may be purchased. That way the shrouds will be measured and built exactly to the length you have. The turnbuckles don't need to be Navtec since they are out of business. That way if a slightly longer or shorter turnbuckle is used, the rigger can compensate the wire length.
If you can't find someone closer, I used Andy Schwenk at Northwest rigging in Anacortes Wa. I replaced all shrouds and set the rig, then sailed to Hawaii. Rechecked tensions here,and they had not changed. Andy is a sailor and racer. email is "email@example.com"
There are a couple of rigging shops in Portland. I don't have any experience dealing with them but found them online. West Coast Sailing, Rigging Products Inc, and Schooner Creek Boatworks. Schooner Creek is well known and might be the first place to try.