I'm 50/50 on this one while it's enticing to see a pre-approval with a higher limit than almost all of your cards combined it's a CU and they typically get HP happy when it comes time to make changes like a CLI. However, on the other hand I have some CU cards that offer up some hefty CLI's w/o even asking. About 50% of them have upped their limits w/o asking by at least 5K/card at this point over several years.
I don't really think it would be an issue with your other cards looking down on you for taking a bigger offer and adding 1 account to the mix. It's been 2-3 months since the last one depending on how you count the months.
It's your decision, waiting until Oct would probably be ideal for spacing things out just a smidge longer, and it will give the others something to compete with when they review your accounts for CLI's.