I use both Solo1000 and Titegroup. Once I run out of TG, I'll probably switch to Solo exclusively.
HP-38 will work, but a faster powder will result in a softer recoil (sounds backwards, but it's true). See the burn rate chart below. Popular 9mm cometition powders are N320, Ttitegroup, Solo100, etc. They're all near the top of the burn-rate chart.
Heavier bullets will feel softer: Just like a .45 producing a shove, and a .40 producting a sharp, snappy recoil... A heavy bullet going slower 'feels' softer, even if it has the same energy at the target.
I shoot 147gr bullets exclusively.
To save money, my recommendation would be a 124grain bullet from Precision Delta or Montana Gold. Order a case (3,000 or so) and get your powder in 8-lb jugs, and you'll save a lot in the long run.
I would use up your HP-38, and then consider switching powders. Do you shoot mostly indoors, or almost exclusively outdoors? For outdoors, I use a www.blackbulletsinternational.com Moly-coated bullet with Solo1000. Titegroup will not work with lead or moly because it smokes like a musket.