I have used the upvc strip, the same stuff that I used to overboard soffits and fascia.
I found it very flexible but it required a few wooden blocks to fasten to
It's not a cheap option but Lunns ( Hampshire I think) are a plumbing outfit
On their website look for tap inserts/ splines or something like that
You count the splines on the end of your piece and go to the relevant section, looking for your body.they offer measurements top and bottom to try...
Our firm use a variety of filters and I carry an oil filter wrench to undo the various different size lids on a service, if a customer doesn't have a spanner.
On the upside I can change the oil filter on the van