GRT has had a lot of powders and a fair number of cartridges added since our last discussion.
It may be more viable, now.
As for QuickLoad...
I don't think it is the right answer for you.
I bought QL for use with some of my wildcats and cartridges with limited published data (like .458 SOCOM, .475 Tremor, 6x45mm, .444 Marlin, .480 Ruger, .307 Win, .17-223 Rem, .327 Federal, etc.).
For those cartridges, it has been almost completely useless.
QL does not do well with most straight-walled cartridges, particularly those running low pressure. The program also has extremely limited (often incomplete) data for uncommon cartridges, like .307 Win, because the sample set for testing was limited (if the cartridge was even tested - some are just dimensional entries in the database, with no 'tuning' done).
Everything in QL can be tweaked and tuned. But that isn't as easy or straight forward as it sounds, and one must always be careful to leave the original files unmolested. There's also always the question of whether or not you're changing the correct values in the database files. Just because a few tweaks gets the muzzle velocity to match actual measurements, and peak pressure now represents something more plausible, doesn't mean that it will scale reliably when using a different bullet or changing the powder charge.
I like having QL. I really like being able to run all kinds of theoretical loads and get a prediction (which your experience with the components, and the program, can be weighed against for how accurate it may be). It is exceptionally good for getting velocity predictions with common cartridges and popular powders and projectiles. But it is terrible once you play outside the box. QuickLoad's 'box' is bottleneck rifle cartridges, running ~42,000+ psi.
...And I bought it for a very similar purpose to yours, and it is not helpful in that regard. I would like to think my experience is an unusual one, but I've heard the same story from many other people that wanted to work with an unusual, uncommon, or unpublished cartridge, couldn't find data, thought, "QuickLoad is the answer..." and quickly discovered that random loads off the internet are more accurate and (possibly) more reliable.
If you do choose to buy QL, remember the most important thing:
Garbage in, garbage out.
You must be vigilant in feeding the program good data, verifying the default values in the database, and double-checking what the program spits out; as the databases do contain errors or omissions, and we humans do make data entry mistakes.