Welcome to ECF. 0.25 ohms is around my favorite resistance... It sounds like you just need some experimenting and experience; we can give warnings and what we do/don't do, but wattage is preference. I like hot vapes and fast rampups (coil gets hot faster) so 66 watts is okay to me for 0.25 ohm coils. 55 is perfect for long hits. But everything about vaping is preference, after safety rules are looked over