there is some netting out of the rookie pool that results in it not fully counting the $5.5
for every rookie signed, it knocks a $850k minimum contract guy out of the top 53
so: 6 draft picks x $850k minimum player out of the top 53 = $5.1 mm
that means the $5.5mm rookie pool will actually only take up $400k in additional cap space
Yeah the top 51, but it's a red herring. The only cap that count's is the final 53 for which we have $182.5m.
Maybe your 7th rounders don't count against the cap in the off season because they don't make it into the top 51, but if they stick they will do when the top 51 rule ends.
For the purposes of cap management and cap space it's best to always work with the final 53 number as that's the only one that really matters.
It used to always boil my piss when Mitch would write a whole paragraph about how if we sign X guy for $2m it's only costing us an extra $1.2m against the cap because it pushes X guy earning $800k out of the top 51. It's crap.
The top 51 ends at the start of September. If a guy has a $2m cap hit he's going to cost you $2m against the cap by the time the season starts.