Umm...Tough choice, it will still affect you, just not as strongly as others. Go for 2 hits for sure, rather than 1, I think you'll still have a decent effect from it. If this was just gonna be a solo trip and you have a limited amount of LSD, I'd say hold off, but if it is planned with friends and you can always get LSD again later, go for it, its not the biggest disaster in the world if you don't trip as hard as your buddies, maybe a slight waste of money, but its all in good fun I guess, eh? You'll still have a laugh at their antics with your possibly dulled effects and just smoke a bunch of weed and its all good I say.