couple of observations.
"gift" spells. Once you have bought your first of these, doesnt matter if its Life, Sap or Stamina, you will have access to Hitpoint Credits for your spells. From now on, instead of learning the "readymade" version of spells, scroll to the bottom of the trainers list, and just buy the upgrades. this way you can avoid paying for time credits if you dont intend to use them. This applies to any magic skill*... once you have the 1st level stanza, all further improvements can be learnt as upgrades
*doesnt apply to auras/self heals/speeds/invulnerabilty tho
Fear, and other afflictions. It may be tempting to grab and use the upgrades as soon as they are available, but I would advise checking your success chance on your old version vs the new one. You will find that with a newly acquired upgrade, your chance of successfully casting is much lower, until you go up a few more levels. Mobs may break the lower level link more easily, but your odds of scoring a link and getting xp are better with a weaker spell.
Ricochet works Ok in heals, and offensively ( I love the mental imagery of a Ricochet'd Rot spell.. chunks splattering everywhere
)- but I havent set up identical bomb/ricochet spells side by side to check the difference. Spray works as a narrow cone directed away from you starting at your target. Apparently this is exactly the same as the Autolauncher. It is usable offensively, tho without the ranged ability to shoot&scoot you cant keep your targets in a line.. but with heals I cant see it being worthwhile.
After a while you get so many magic skill points, you do end up buying everthing on the list
For Remyt, a defensive mage is a healer.. so all the heal spells, with a bomb version set up for use in parties, when you get past level 100 and have double spells, set up a hp+hp heal, a hp+sap heal, and a hp+stam heal, again with bomb versions. Single spells are more economical than doubles, so keep them available for lower threat environments. Fear is probably the emergency spell of choice, so keep it handy also.
Offensive Magic pretty much relies on the elemental damage spells, afflictions not being reliable enough at lower levels. Depending on how many skill points you have, get a few different types of elemental damage spells, and stick to hunting what you are effective against.