Needle valves

Reconditioning the carbs. Have acquired a few various fuel needle valves over the years. Some have had little use but not sure if you can check the inner needles for wear or which of the few types around are the preferred. Or just to throw any used ones out. All in the photo are for a 175CDSEV carb found on most Aust and USA Stags. The top one is verified as new and genuine Made in UK Zenith VITON tip needle, the other 3 are used and I am not sure of brand. Also should I be using a preferred type of gasket cement (if any) on any of the gaskets? I remember having hot starting issues straight after last workshop recondition. They fixed this by removing entirely the float chamber emission port valve and problem went away! So I am not putting this back but not sure if affects anything else.