I haven't tried the Dancing Bears as I was told they are a similar dose to the Ganesha tabs, which I enjoy enough so just use them. I understand exactly where you are coming from with wanting to up the dose. I would say definitely have a go on those Avatars I would say 1 was comparable to 3 1/2 > 4 Ganeshas (or more) easy, you'll most likely get the kind've acid trip you've been after those past few trips - I certainly did. One was enough, but not intense but that doesn't mean it isn't a good strong trip. Definitely try one first, just in case, as for some people 1/4 tab of these would have them satisfied.
Regarding mixing with MDMA, I would treat carefully, it might be worth trying the Avatars first. Although MDMA+LSD can be a life-changing experience it can also turn into a horrible one if you don't get the dose right, most people would recommend half of each (more so the MDMA) that you would use in a night, so say for example you normally take 4 tabs and 2 pills, take 2 tabs and 1 pill. I recommend also eating the MDMA as your starting to really strongly get into the trip around the 4-6 hour mark, depending on whether or not you want to be feeling the MDMA after the acid. I'm sure someone can elaborate on this subject more than me.