For your set up (i.e., no aerobars)...
I would get the Dark Speed Works or Xlab Bento bag and use that for the stuff you already use it for...it shouldn't be bulging too much. I would put one bottle on downtube, nothing on seat tube and 1-2 bottles in a rear Xlab carrier. I would at least consider putting all calories in 2 bottles (or one bottle if that is all you need) and use the third to start with water and swap out at aid stations. No need to be digging around in bento for gels etc while riding. Depending on Xlab carrier you use, you could also use their gadget to attach two CO2s and an airchuck to save even more space in bento. You could also consider putting a tube under your seat if you need more space in bento
I would get the Dark Speed Works or Xlab Bento bag and use that for the stuff you already use it for...it shouldn't be bulging too much. I would put one bottle on downtube, nothing on seat tube and 1-2 bottles in a rear Xlab carrier. I would at least consider putting all calories in 2 bottles (or one bottle if that is all you need) and use the third to start with water and swap out at aid stations. No need to be digging around in bento for gels etc while riding. Depending on Xlab carrier you use, you could also use their gadget to attach two CO2s and an airchuck to save even more space in bento. You could also consider putting a tube under your seat if you need more space in bento