Trying to maximize my bottles on the bike...

According to the Hammer site and to a few I've talked to who have actually done it you can mix Perpeteum to a paste about like wallpaper paste. If you do this you also need a water bottle to drink from in addition to the calories bottle.

I use 3 bottles in a HIM. So during my IM I used 3 bottles and put 3 more in my special needs bag for the second half.

Dunno if that helps or not but it worked for me. I'm going to do the same thing at IMFL this year as well.

You are limited when you have a single carbohydrate source, you're body will digest/ingest more calories if you're using multiple sources of CHO. You can probably find those studies on must product websites. I don't have them handy at the moment.

I personally, have two bottles on my bike. An aero bottle which I squeeze my fuel source into just prior to the an aid station, I grab a cold water from them and top off my aero bottle. This dilutes the mixture and gets it cold and refreshing. I'm just not a fan of sipping on concentrate and then washing down, I don't want to break position that much and it upsets my stomach.

At special needs, I grab a new fuel bottle and repeat on the second half of the course for IM. HIM, I don't need the extra bottle.

I use Heed (plus some solids).  I can put 5 scoops (which gets me through an IM) into a bottle.  That one goes on the downtube.  The other bottle (mounted 'torpedo style') has water.  I dilute as I go (sip of Heed, then sip of water).

I swap the water bottle out on course.  Other than that I'm self-sufficient and carry only two bottles.  (Solids go in a bento box.)

Not sure about heed, with Infinit I can use a tripple serving in 1 bottle, so 1100 calories per bottle.  1 bottle for a HIM, 2 for an IM.  This probably translates to heed, not sure. You just have to wash it down with water from another bottle.

Once you start concentrating, you are going to have to drink with water as you start approachin "gel" status. 

FWIW, my last IM I rode with a 900cal bottle (3x concentrated Infinit) and 2 gel flasks (~800cal) in my jersey pockets.  Got some added calories through sports drink on course, but obviously used water fairly often to dilute my fuel sources.  Never need to stop.  Never need to mix on course.  Only 2 bottles on my bike (one frame, one aero bars). Worked well for me.

Why not just learn to drink what they are giving out on-course?  That way, a problem with/loss of your feed bottle is not a catastrophe from which you must recover.

I prefer GU Brew in my training and I start with it in a race, but if I need to refill, I take what is on the course.   Rev3 races are good for me since GU is a sponsor.

Concentrated infinit.

1 three hour bottle for HIM (plus 1 on course water, replaced as needed)
2 three hour bottles for IM (plus 1 on course water, replaced as needed)

Payday for variety

That just doesnt always work, my last race served HEED.  I just couldn't take the stuff.  Same with Cytomax.  Not knocking their products but my attempts during training to use them failed.  Infinit works well for me but I have had to adjust the mixture for me.

Remember, no matter how concentrated you make your solution, you still need to grab a bottle of water to hydrate.  Because you are getting you calories does not mean that you are hydrated.