Det, SPS, DH clarification

[IceBlueNinja]

Sorry if there is any old posts about this. I no doubt know crit is a must for every class (3.9k almost 4k cant wait). I been having an issue on secondary stat in terms of a healer, see det information state it affects amount of healing and dps done base on how high it is. Sps claims to affects hots and dots but usually I hear only blms do sps. Finally healer gear technically do not give DH which though I see the meta for healers is if unable to meld crit cause the gear already gave the amount of crit they will instead do DH over Det. Personally since sb (which is when I began learning about melding materia and what does it do) I go for as much det possible after I meld all the crit I can. A little research of DH vs Det I saw on a chart of how much affects both heal and dps magic vs DH only affect DPS magic do not seem quite different i believe the number was something of 1.4 increase on heal and dps while dh was 1.8 , I am not sure if the chart is still accurate but, also why some healers may rarely meld sps?