I considered these tools but didn't buy them because they are light weight. I've found that for hollowing I like heavy steel boring bars with a heavy, long steel handle so I can press the handle against my side while I'm hollowing.
Note that I'm a rank beginner at hollowing so take this post with a pound of salt.
If you're serious about hollowing I strongly suggest you buy David Ellsworth's new book, "Ellsworth on Turning." This book has changed the way I hold tools, orient wood on the lathe, use turning tools and will probably get me into making my own tools. For me, this book has become my turning bible.
I also have the 1/2" Trent Bosch tools but also have a Monster Articulated Arm. With the Arm, the stress on my wrists, forearms and rotator cuffs is almost eliminated.
Of course, it's OK to buy your selected tools as they will always find some use when you decide to buy other hollowing tools. Just the nature of turning.
My very humble opinion,
Burt