PA4x61 is actually smaller than the 970! Fits in the same bag, but has more room.
I didn't have a huge problem with the 970, but I sure like the Korg better. Main items are controls, vocal processing/harmonizer and the wonderful SONGBOOK! The light (flimsy) touch doesn't bother me, nor do the smaller keys, but that would matter more to a piano player.
I have played the Tyros every time one came out, and they are just big and clumsy. The lead sounds are very nice and the audio drum kits are excellent. The midi drum kits still are lagging behind the other companies.
Same can be said for the 970.
As always, IMHO!
I once had Roland E80 and E50 at the same time, and, trust me, the E80 never left the house! There was about 45 pounds difference in weight and very little difference in sound.
That E50 was a real workhorse, and never got enough credit for what it did!
Back to the subject, I think it's a wonderful plan to have both Yamahas. Go for it! You will find yourself not ever taking the T5 out of the house!