Take the A5 magnet from your 498t and put it in the 490r and install an A8 into the 498t. You will then essentially have a Custom 8 and '59 Neck set for $5. I did this to my LP Custom and I'm very very satisfied. Those pickups are never leaving that guitar. It's like a whole different set. I got the idea from here and its not forum folklore. It really works and its awesome. And if you decide not to I may interested in one or both sets.
I thought I'd got the TB for both, as they're the modern Gibson spacing bridges. Turns out I bought the SH for one but I don't imagine there being a huge problem.
Not necessarily brighter and tighter, however it is a tight pup. Some say it is bright, but that's not what I'm hearing...I hear a very even tonal spectrum. Definitely more mids than the 59. I also don't hear the Jazz as being very scooped, at least not like the 59.
The Custom has way more mids than the C/59 hybrid. What you are hearing is the very strong tight bass and the almost extreme, piercing highs of the Custom due to the ceramic magnet which makes it seem like it has less mids.