Ok here's my findings so far on research...

You cannot research spells that are beyond your current characters level.
Being a level 15, even with research at 150, 255 or whatever, you will
always fail on a level 16+ spell you are trying to combine from research.
Also, your research skill level is also checked. I have NO clue what so
ever, but hearing someone with a skill of 17, researching a level 16 spell
gets an increase is a good foundation to start with. I myself keep pouring
my training points into research, currently I have around 33-38 skill in
research and will continue to burn points in it. I did get two tomb pages,
43 and 44 that I failed on trying to combine them. I've recently gotten
pages 55 and 77 as well. I assume the tomb page numbers increase when the
level of the spell increases, but again, I do not know for sure. I've
never seen a skill gain from all the spells I've made (color shift, mes,
endure magic, strip enchantment, tepid deeds, levitate, and disempower), I
always get the message it's trivial for my skill and make a spell from
combining the pages. All my skill is from training.
I would suggest two routes for you on research, do it with the intent of
supplying everyone you can with the spells you make, using training points
to help push the skill up into the level needed for the research you want
to do. This is the case I am following, I charge two pages for one
completed spell, nor full market price for it. Else you can let someone
else pursue research and supply you with the spells they come up with.
Sooner or later, we'll all have the spells from research, just a question
how important it is to you at the time. I am one of three I know of on
Rellos Zek that are working research very hard and have a very good supply
of pages coming in.

Hope this helps,

Telan Ka`Rlaah of Rellos Zek