Bride Lyn dilemma

Well if you want a high stat Bridal Lyn then merge would be the best option (also the option I would choose personally) but if there is a healer you really want dazzling staff on since it is a rare skill like maybe Lachesis or Nanna or someone then I would say go that path.

If you have the resources to get her to +10 then I would say merges are worth it, but if your F2P you might be just better off giving away Candlelight+ and Dazzling Staff 3 to another healer you would like to build in the future.

(I hope it's not too late!) Don't merge her, +1 isn't going to do a major difference but her rare skills will do. Hold on to the extra copy and give either the weapon or Dazzling Staff to another.