Acrylic varnish on wet plate is NOT archival.... Sandarac is. Mark Osterman has seen issues with plate longevity with using acrylic varnish
aswell as other substituted chemicals such as denatured alcohol instead of regular grain alcohol. Wet plate is not rocket science and is well documented. Use what works and is tried and tested. Sandarac is not hard to figure out and use once you know how.
Listen to Andrew...short cuts in wet plate generally get you to where you do not want to be...from cleaning the plate to varnishing it. K