Dont remember my stats but i always hit over 500 collectablity and am able to collect 2-3 depemding on proc.
I do:
1. Single mind--> impulsive appraisal
2a. If discerning eye procs then do another single mind then methodical appraisal
2b. If no proc then discerning eye--->methodical appraisal
3. Discerning eye--> methodical appraisal

If you get the proc in step 1 you will be able to collect 3. Cant remember my stats exactly but both gathering and perc are above 600 and you need 600gp for this