House built in the mid 1990's...toilets always have been terrible.
What brand(s) are they, now? Do they have exposed trap ways? If so, are the trapways smooth and sweeping or are they sweeping then take a 90 degree turn, or two?
Since you have 5 toilets the best option may be the Drake 1.6gpf toilets, CST744SL-01. You'll probably want to replace the one toilet that gets clogged the most as a test. Switch over to Scott 1000 sheet 1-ply t.p. and only use about 2 feet at a time. If it works, as I expect it to, then you can replace the other four.
A word on planning: since you have 5 toilets, one of them is probably in a hall way, and at least one is near the children's bedrooms. You may want to consider making the toilet nearest the children's bedrooms a regular height toilet, and maybe the hallway toilet if your friends bring over their children. It may be harder for a six year old to use a comfort height toilet, for example. If you have a vanity that is real close to the toilet you will probably not need to buy the pre-requiste right hand flush toilets since the Drake handles are at an angle.
My house was built 1979 and it had Briggs 3.5g toilets. They never clogged but it would take two flushes to completely clear it of solids and floaties. I have the Drake CST744SL-01 and have decreased my water use to about a fifth. (The Drake handle can be held down for no more than 1 second and it flushes about half a tank, or about 0.8g, when evacuating urine.) After seeing how much water is actually being used in the 1.6gpf Drake I will be picking up a 1.28gpf Drake, tomorrow. I expect it to evacuate just as well as the 1.6gpf Drake. It will be a regular height Drake because it is the hallway/children's toilet. Gotta think about the next owner of the house...
If the 1.6gpf Drake works well, then you may want to try the 1.28pf Drake before committing to the purchase of the last three. No, I wouldn't be surprised if by the end you go to the nice looking 1.0gpf Drake in the Master bedroom. But definitely try the 1.6gpf Drake as a replacement for the most clogging toilet in the house. (The Drakes all have nice large water-spot sizes, over 80 square inches, including the 1.28g Drakes. I consider water spot size important.) Save the master bedroom toilet for last. That's the room that you will probably want to install the UltraMax II MS604114CEFG in. By the time you get to it you will know whether or not you made the right choice.
In 2011, the San Francisco Chronicle reported that, while low-flow toilets are estimated to have saved the city of San Francisco 20 million gallons of water per year, the reduction in water volume has caused waste sludge to back up in the city sewer pipes that were designed expecting a higher ratio of water to solids.
http://en.wikipedia.org/wiki/Low-flush_toilet
I assume that in their zeal to save water, especially now that there is a water shortage in CA., people have cut back flushing after urinating. This usually leads to bacteria growth in the bowl and may include rust/lime/mineral buildup. You don't want to do that with a Toto; flush it every time. Some will say that even for urine flushes it should be flushed fully. It may depend on your locality, the condition of your pipes and whether or not there is a water shortage.