Try the stem that comes with it to compare. That is your "baseline" testing. Your out of the box, fully charged solo with normal stem packed should give you an idea if your SOLO is working properly.
In general most of us would say that the size of the bowl for the normal stem and normal PVHES stem is too big. Which is why someone came up with the 'domed screen' approach, ( check this thread for it) and PVHES came up with the "shorty" stems/GONGs which are 30% smaller.
Even with a shorty stem, I can still fit a full Pax-sized load in it.
Another tip I do for smallish packs, is use AVB to bugger the pack if you have a small amount of fresh herb.
All of the above are just suggestions and the herb, how it's ground, the humidity in your area etc.. a million other variables could impact your vaping.
My first SOLO experience was huge hits off a fully packed OEM stem. I could not handle it and it took me 3 sessions to get through a fully packed OEM Stem. (about 1.5 PAX loads). I'm built like a NFL lineman so it's not like tiny whisps knock me over...
However despite being a huge fan of the SOLO, I would say that the Da Vinci and Pax both offer a more immediate indication if your bowl is ready/still waiting or spent. The SOLO has a higher learning curve than both IMO. It's quite easy to have a pack sitting there and hit it too late or too early or too hard or not hard enough etc...
EDIT: Just noticed Dreamerr mentioned setting of 4.
I found that with my SOLO< (newer model) 4 is like LOW setting for PAX. 7 is like medium/high for PAX.
But for a stem draw, 4-5 was max temp for me due to harsh/heat etc... But with a water bubbler + PVHE, I just run with temp 7 all the time.
The PVHE allows air to come in, but if you draw too much, that air will be cool, which reduces efficiency big time if you draw too much.