There’s a new nipple washer available from Sapim — the Sapim MS washer has a generic V-shape profile compatible with all nipples (compare to Polyax washers with a Polyax-shaped cup). It has a thick, flat bottom for superior weight distribution however needs a flat resting spot 7.7mm in diameter. Where applicable, these stainless washers will impart a lot of strength.
Not much information is searchable for Sapim MS washers so I’m posting the product sheet to give you information from the source. Note carefully: my measurements put the diameter at 7.7mm compared to the nominal 7.4mm. Get MS washers and three other types of nipple washer here.