Making wire cloth air filter. HELP on opening sizes.

http://www.mcmaster.com/ sells wire cloth for use as air filters to filter out various sizes of debris. Im going to buy some of this and make my own air filter to go over these turbo inlet velocity stacks I just bought for my T-61s.


So my question is, what size openings do I get? To see what im looking at, go to the site (mcmaster) and put a search in for "wire cloth filter" and click the only option. Then scroll down on the right side of the page some and there is a filtration chart, and just below that, the types of holes offered. Im going with the "square/rectangle size" as it will flow the best. Car is daily driven and turbos are inside the engine bay...current filters stay pretty clean. So I was thinking maybe .020-.030, but there are a TON of options in the pull down selection menu. The chart helps, but I just dont know how much flow that it would restrict...and I would like to just run one layer with maybe a thick, high flowing layer layed down before, for support so the turbos dont try and suck the filter in too LOL.

Thanks for any help! I would like to order today if possible

Ok, I did order yesterday...and went off all the information I could find via searching sites like "honda-tech" and "theturboforums". If you try and go with very small opening to filter out dust..basically replacing a regular filter, it just creates a huge restriction...turbo honda guys were loose 20HP with them over just open pipe and 10HP vs name brand large filters, with 400WHP cars.
However turbo mustang guys were gaining a few MPH in the 1/4 vs name brand air filters, when they used window screen. In other words the opening per square is .054 as verified by my window screen and the stuff I ordered allows for almost 74% of open space, being that the wire is VERY thin T-304 SS. I also ordered a second layer that has .21 inch openings with thicker gauge SS wire. It will go down first to prevent the thin wire from being sucked into the turbo and has a slightly more % of air space open.
This should improve airflow ALOT over my current filters...and I really have no choice anyways. 4 inch opening on these new turbos...3 inch on the others, so my current filters will not work.
And I only have about 3.5-4 inches of space between the turbo and the battery.

Basically this will keep anything larger than beach sand from going into the turbo...so I think that will work.