Sounds like you got the right idea to me. I would say drop 1.5 - 2 hits of acid though.... unless it is strong (above the 100 mic level). 15 mg of 2ci is good. I have done the combo twice now.
First time was 18mg 2ci followed by 2.5 hits of average potency acid. Went to a rave... and was in a really good state all night. I was never overwhelmed, but was tripping real hard... It was obvious because it was nearly impossible for me to slow down all night. Someone gave me glow sticks and they were my companions all night long. This was one of my first doses I had taken out with 2ci. My previous trials had been at home in low doses... Probably my 3rd or 4th time using this material now that I think of it. I'm glad I ate acid with it... I think it was better than if I had not eaten any acid. Still don't understand why yet or i don't remember... gotta dig up some writings on it.
2nd time I used this combo I ate 10-12mg 2ci and 1.5 hits of some average potency acid about an hour later. 2ci usually takes 1.5 hours to kick in for me, and acid kicks in 45-70 minutes for me usually. With acid I can get an alert or 2 30 minutes after ingesting, but I'm not really there for another 20 - 40 minutes. 2cI is pretty gradual starting around 45 minutes and reaching the peak at 2 hours or so. I wanted to be ascending the peak 3 hours in... I figured the acid would add its own to the mix. I dosed with one other person... who took the same dose... We had a trip sitter (my roommate) though it wasn't necessary... I just eat drugs often, and he doesn't, but he has fun when I do so its cool. I can get pretty manic... Anyways this was a winter trip. Lots of playing in the snow in the early hours of the morning. Played with some glow sticks... poured the fluid into the snow... belly flopped into the snow... ran around jumping all over the place... Came inside and listened to some music... I think I put in Clouddead... love them. Really good vibes all nights. Both materials are pretty stimulating for me. My first experience with the combo especially so... I feel this experience was a little less so. I felt very comfortable the whole way throughout. everything looked warm and soft and there were mild tracers throughout the dark room... the only light being blacklight. did a lot of dancing. That was fun.
Uh... rambling now...
All in all... good combination. I had more enjoyable, or comfortable, experiences combining 2ci with acid than I did with 2cI alone.... I like 2cI though... I find it interesting and I tend to become creative on it. I particularly like to draw and write while using 2cI. when combining with acid it makes me prefer dancing and adventuring... anything that gets me moving.
I wouldn't expect you to have a bad trip... If you want to trip hard, 15mg and 1 hit acid probably won't do that. It will definitely be enjoyable though, especially if you are already comfortable with both substances. I haven't really ever been overwhelmed by 2cI... and adding acid mostly just made things more exciting.
My recommendation is 10mg 2ci and 1.5 hits of acid as an at home dose.... or the 15mg and 2 hits as an adventure trip.
Good luck. Enjoy!