I think you need to ask yourself what you want to achieve from this beer
Seeing what haulertau Blanc tastes like when doing a smash with kviek I'm imagining some white wine notes and a dryish beer with a citrus twist.
Than maybe smash is perfect even adding some cane sugar to make it a bit thin and snappy? Your call.
Um 5 minutes or flame out Na not much difference just a couple ibus.