I made an LCD screen cover from ABS. Clear as clear can be. Even had Protomold make the mud tool. Looked great, other than the ejector pin marks. But what do you expect from a $3000 tool.
Never spec-ed delrin. Has such a nice feel when you rub two parts together. I do think the ABS will give you a more audible snap. Assuming it is a small part, shrinkage won’t be much of an issue. Have them run it in both resins before you finalize the spec.
Accura White is an alternative to the clear. But if your printer has the white, they will have the clear.
Again, I’m assuming this part is no larger than a quarter. Since it is small, I would steer clear of any FDM process, you will not have the needed resolution and it will interfere with the functionality of a small spring clip. You need to stick with the resolution of an SLA. If your printer doesn’t have the Accura resins, ask what they have that will flex similar to ABS. Maybe you get lucky.
If you want to simulate delrin, sand the parts smooth, spray with a silicone spray. ABS will bite slightly harder than delrin.
Any particular reason you don’t run the part in NA and evaluate it yourself?
Also, with machining, again an assumption, but I would think you would have a 1mm wall. Hard to machine something that thin with such a low melting temperature. A block of nylon may hold up to the stress a bit better, but then again, maybe not.