Yes definitly get non projected ( BR7ES vs BRP7ES)
Id always get 2 or 3 random counts of knock in the higher gears whenever I did a log and when I installed them there was no more knock .

Now dont go thinking this will allow you to turn up boost, or add any more timing, it just makes your pulls more consistent. The projected tip heats up and since it protrudes out so I guess it acts as like a glow plug when its hot enough. Dont completely take my word for it, do some research yourself if you want to get a more technically correct answer for why, but I do know you should run non projected.

You will have to find what gap works best for your motor yourself, but it will likely still be within the range that I suggested.