Pretty clear cut choice in favor of Sunday which will be post-frontal, dry and pleasant while Saturday will prolong the string of ghastly weather we have been enduring.
Assuming no rain on Saturday about the best to be expected is 4,000 ft msl, probably with cu. Sunday looks blue and not particularly strong with the forecast top of the BL 4,000 ft msl.
Wind NW ~10 kts Saturday, NE ~10 kts Sunday.
QV Friday September 17 1200Z