The non spring loaded pin shouldn't have an issue with a Clapton coil? I have a Tobecco super tank on the Sigelei now. With the Sigelei being an older mod without any of the news features, just want to make sure it's safe.
Spring-loaded shouldn't make a difference what shape of wire your coil can be made from. Flat, round, wound (Clapton coils are just made from wire that's had another, thinner wire wound around it), it's all just "load" to the mod. That one can fire loads as low as .15 ohms, and up to 100 watts. (I'm not sure if it can hit 100 watts
at .15 ohms, sometimes those limits can't both be reached at the same time.)
As far as the non-spring-loaded pin, just make sure to screw your atomizer (any atomizer) down just enough to make contact with the fixed pin; don't wrench it on trying to make it sit flush, or you'll compress the pin and cause further issues.