If it was me I would sharpen at 15 per side and try it out. Then you can always make it more obtuse easily if 15 per side is not working for you. I think it would be harder to make it more obtuse to start like 25 per side then want to come back closer to 15. You'd have to take off alot more steel that way. I don't have an angle checker thing but from the paper that came with my dmt sharpener I estimate my delica and pm2 are around 15-17 per side and I think it's great. The edge holds up without anything crazy happening to it and it slices very good