Is (-)5 positioning while in a press defense really a press? i am at a disadvantage in rebounding and i am thinking about playing this defense to help on the boards. any insight is appreciated.

Hmmmm this is a difficult question with the new engine coming out, so under the old engine, this would lead to less steals, better defensive rebounding, and your opponent taking and making a lot of 3s.

The -5 is kind of the RNG defense. I'm not sure if you are a math guy, but basically imho the -5 causes your opponents average points per possession to go up, but the standard deviation to increase as well. Its a lot of rolling the dice, which can work, and can blow up in your face when a team of average shooters goes 12-20 from 3point land, which will happen at somepoint.

As others will be quick to point out, the -5 can result in a team of good perimeter shooters going 4-20 as well, so it all depends on your luck, but giving up 40% shooting from 3 is likely.

You're also increasing your risk of fouls on those shooters. Try it for several games, see if you like the results.