I exclusively reload, carry, and practice with +P, but the key word here is reload.
As far as the availability of +p reload data, it is abundant. Hodgdon has plenty of published +P data, so that's a non issue.
Can't help you with recommendations of where to buy factory ammunition, I don't shoot it.
If it were me, and it was at one time in my life, I would buy an inexpensive single stage press, some dies, and the necessary components and begin rolling your own. The savings alone is just icing on the cake. But the best part is having the ability to tailor your loads to your liking, shooting the very best ammunition obtainable, and the ability to shoot more are the real advantage, IMO.
I can get bulk jacketed bullets for .07 - .10 each, which works out to under $6 per 50 round box of +P at the low end, and about $6.50 on the upper end. And my carry rounds run about $15 per 50, that's for a good JHP, XTP, or Nosler, Gold Dots are about $1 or $2-ish more for a 50 count batch. All said and done, I could practice with top quality JHP's for less than or close to the same as what it costs for a box factory el cheapo junk.
GS