Buffer Triggering with auto replace and fade

Hey all, sorry for my silly title, not sure what to call it. I'm doing sound for a dance performance and I'm trying to write a patch that allows me to trigger audio files from one of two buffers. The idea is to use only 2 buffer objects to save resources, even though I'm going to trigger many sound files. While one buffer is playing, the other will replace it's contents automatically and wait until I press a key, which will switch the playing buffer and load the other. I want to include the ability for crossfades between the two, which is where I'm running into problems. I've managed to get the buffers to crossfade properly, but if I make the fade longer than the length of the buffer, everything goes wonky. I need to either find a logical way of dynamically changing the fade maximum so it isn't able to be longer than the buffer, or I need to change the way I'm approaching this patch. I'm using a lot of counter objects, and if they go out of sync with each other the whole patch falls apart. Any suggestions? I guess I could just use ableton haha but I've actually never used it and would rather do this in Max. I'm on Max 5 btw. Thanks!

ps. sorry this patch is so messy, work in progress :)