Thank you all for the replies.
I do have a digital gauge, but still not have enough experience to match the vacuum loss to a specific issue...

Just be methodical. Hers few tips:

-Clean working space helps (i vacuum my small workshop befor applying vacuum bag) 
-i apply perimiter seal tape prior to anything else so it seats on clean sourface(add pleats later on)
-seal silicone inserts from the inside as well
-watch for stray fibers
-make big enough bag
-double tape on pleats
-take your time(you will get better and quicker soon)