Eylis> to be honest, I'm not sure. I think they might be taking bit too little space, but you should try to ask Firn about it in rejected thread, I'm no help when it comes to custom bases >.<

With> I'd take away horns from first stage. There is really no need for them and them showing up already mid sized in 2nd stage will give more impact to change in him. Same goes for some other things, like:
First: scales in legs+sash+light red hair
Second: leg scales changes +fins, longer hair without color change, horns in mid size, thick necklace, no ear change, eyes get darker
Third: serpent body+ longer hair with final, dark color+ horns fully grown with rings, small wings, emblem, no ears change
Fourth:cloth+armor, fins, eyes get final color, larger wings, fully developed ears
Fifth: his final look

I changed stuff about hair and eyes color, horns, ears, wings (and this applies to most of knuffel changes in general, but I'll use those few as examples) etc for one reason. If you go with: small horns>mid horns with rings>big horns, or light color>mid color>dark color etc between stages, you automatically make change between stages smaller. You take away impact from evolution and make change less visable, stages more similiar etc. However, when you go mid horns>big horns with rings you make horns showing up and changing more dynamic and visable. Same with color. If you make color change gradually through few stages, it will be less visable in final outcome, but if you make hair light in one stage and dark final color in second, you make a good, visable change that will be noticed right away. Same goes with ears: ears are a small part of body, making them grow through few stages makes changes in them between stages less visable (unless you're going to make them take half of space, o.o), but if you only add big, pointy ears in stage 3 or 4, change in knuffel will be noticed much easier. Number of changes is one key to make good evolution, but way you show them is second. Of course you can make big elements change even through all knuffel's evolution, but if you want small elements like horns, ear shape, or hair color to be visable and add to evolution, try to make them evolve in more dynamic way, in 2 stages instead of 3-4. Of course you still can make some small elements evolve longer if you want to, but if you make all the elements evolve that way, you makes stages too similiar even though they have lots of small changes. Err.. hope I'm making any sense here >..<