Depends on your play-style. If you are going to be focusing on buffing your weapons then use the clutch ring, but if you are going to try and use the sunlight spear the majority of the time then you should use this for the extra 5% damage boost.
The Clutch ring as you probably already know buffs both lightning attacks and lightning buffs by 15% (both miracles you have listed) but also increases damage taken which may result in a glass canon build depending on your armour used. This ring as you can read above flat increases your miracles damage by 20% which only affects damage miracles not buffs or healing (sunlight spear not lightning blade) and has no debuff on your damage absorption so if you are play using damaging miracles then your bst bet is to use this ring.
So you are probably better off using the clutch ring if you are able to not get hit due to the boost to both of the listed miracles, but if you would prefer to keep your damage absorption then your best bet is to go with this ring due to its larger boost with sunlight spear and no reduction in damage absorption.