Both ways are working and potent, some say one is better then the other, in a way it's better to do morning half then evening half as this will renew the energy through the day, keeping you safe at day and safe at night when you're sleeping , prioritizing "Renew of energy" , also this should be done especially if you can't handle the entire amount of vibration [108].
As per number it has been confirmed the 108 has been a mistake as this is more related to Saturn [Correct me if I am wrong] , therefore you should use a Solar number , some number that are recommended are 100 , 110 , 111, Affirmation should be done 10x times , before we we're doing 8 and mostly 9x but 10 it's Sun number and therefore more powerful and potent.
The above is mostly for protection spiritual workings , thing is if you want to do a working properly such as one form money with Lakshmi then you should do it ONCE a day, at the same HOUR preferably if you can, if you can't do at the same hour then it's fine but such working should be started at a right time [Planets, avoid void moon] , check the JOS Calendar for that.
If you start it at let's say Thursday at Sun hours at 13:20 PM then it would be preferably if you could do it again and everyday around 13:00 - 14:00 , giving the working an exact of nearly 24 hours to renew the working , making it and progressive all the way within your soul and attaching more onto you, giving you more eventually in time and with constancy.
Advice for spiritual workings regarding money:
This should really be doing and started around 13:00 - 15:00 when the Sun is more potent and powerful on the actual sky, before any money spiritual working one could also go straight outside , sitting in the Sun energy and breath and absorb it's energy doing affirmations to empower himself for his working. - TESTED AND WORKING AS A CHARM!
*If you could do this before every day working then this would be extremely beneficial , probably more then the working in itself [but both helping each other and combining well]