Using one of the more advanced modeling devices (Helix, Axe-FX, AX8, etc) is a large paradigm shift from simply plugging into a 100w tube-head w/4x12 cab.
Do you have access to a FRFR PA speaker?
That would provide SPL levels similar to an amp/cab... and would provide a much better perspective from which to gauge the Helix.
Also, it takes a while to get up-to-speed with Helix/Axe-FX/etc.
When I first got the Helix, I didn't like the bottom end (same is true for the Axe-FX II XL+ and AX8).
For me, placing a high-pass filter prior to the Amp Block (on all of them)... instantly made the bottom end sound much better (tighter).
Little things like that go a long way toward achieving the desired result.
What I like about Helix:
Once you're up-to-speed, if you can imagine the sound, you can quickly/easily create it.
If you like your particular cab/s, create your own IRs with the cab/s mic'd the way you prefer.
This help take you even farther toward achieving your sound.
Proper monitoring setup is paramount to achieving good results (similar to studio monitors being necessary to achieve a good mix).