So I have a Raven Inverted system but I don't think that the problem is necessarily from the Raven system. It seems pretty normal. The engine breather is a 1 inch straight nipple off the accessory case. Standard issue I am sure (size and angle). Which means the other end of the hose also needs to be a 1 inch nipple. I am attaching the oil separator to the right side of the engine like all of them I have seen. An AN842-16D (90 degree elbow) is readily available for 15.00 or so but I cannot use that one where I wish to place the separator as it hits the mount. I would have to go further forward but even there I may be dodging the mount. So I want to use a A844-16D (45 degree) but it turns out that is a rare and expensive part. I found new ones (some old stock) from 243 to 50 dollars. I found some as removed by one place that had 39 of them for 100 bucks each and one place that had 5 as removed for 20 each. So I have one coming. But.... I ordered what seems to be the only hose choice (MiL6000D hose from ACS http://www.aircraftspruce.com/catalog/appages/mil6000.php?clickkey=7466) at 9 bucks a foot for the 1 inch ID. I have seen an older piece of this in the 3/4 variety and it seems flexible with an inner braided core and smooth exterior. The hose I received has a weird spiral cord on the outside and it has a very wide minimum radius as I cannot seem to get the radius needed without it attempting to kink. I cannot believe I am the first one to have this problem. Is there a better choice of hose? Aircraft or otherwise. I have found this at Summit: https://www.summitracing.com/parts/ppe-515101036 any suggestions on this?