There are many danger signs in the practices you describe. We ought to be cautious about various spiritual practices or exercises that have many different moving parts, or complex requirements. We ought to be even more suspicious of unqualified and overly certain promises of success. 
 
At the heart of indulgence practices is a very proper notion that prayer has salutary effects. However, prayer should not be reduced to superstitious practices. We cannot force God’s hand; neither should prayer be likened to magic which seeks to manipulate reality. 
 
Every pious practice and prayer is always submitted to God's will; and through these things we commend ourselves to God's good graces, knowing that he will answer in ways that are ultimately best for all involved.

No, you ought to first go to confession. The Catechism, in conformity with ancient teaching about the necessity of attending Mass says, “Those who deliberately fail in this obligation commit grave sin.” (#2181). Hence you ought to go to confession first. There are some reasons that one might miss Mass that are legitimate such as serious illness, the care of the sick, or some lack of capacity due to weather or distance. So also struggle with work schedules. But in this matter they should consult with their pastor or confessor and also seek solutions.