Hmmm after reading through this thread, I would say this:

Keep going on the apps until you get denials and then keep trying even still.

For example:
I applied for 3 cards on 5/13 and got initially denied on all the them. But I researched and contacted the back offices of them all once 'the letters' came and was able to get approvals on all 3.

In my case, we have no mortgages but we do have a sizable equity line with one major bank. I established that this is our only debt and because of that, the card companies were able to reconsider things in terms of assets and debts. (It actually would be better for one's credit to have a mortgage than an EQ line, btw, but that's what we got for now and so be it)

In one above case, I got a denial from Chase on a card app and so I called them back and asked them to simply approve this new card and do so by taking some of the credit line from an existing Chase card. While they were about to do just that, they ended up instead just giving me the new card with an added limit. To my delight on that phone call, they did not end up even needing to take credit from the other Chase card to make it happen. In terms of what cards have which limits, I have since been able to change the credit limits on my Chase cards by simply calling in and asking them to move the availability around. Chase lets one do this sometimes.

In terms of money and miles...
Well, let's say for the sake of argument that on all your cards combined, you could potentially max out or nearly max out all of them in one day purchases on things like coins, gift cards and a bunch of other things buried within the many threads of this fine forum...

Let's also say that you could do this 3x per month...

Let's say that figure is about $50,000 x3, rendering a combined 150,000 points & miles per month...

Well, then, by God man! I say go for it! And keep it up til ya cant no more!
That's what this place is all about, ryt?

Just don't tell too many outside friends or family. They'll either want your miles or think you're crazy for doing all this or both.

After all, wasn't it the famed ski film maker Warren Miller who once said:

"Ski it, and ski it now, because if you don't, you'll be one year older when ya do!"

MM!