Leveling your stove will likely help some to avoid your pellets hanging up in the hopper - but it also seems to be a pellet dependent thing. The MWP and Crabbe softwoods I burned in past seasons would hang, but the LaCrete softwoods I'm burning this season don't. Pellets with lower density / less compression seem to be more problematic, as do those brands with higher amounts of dust, which increases the static charge and seem to make them hang up more.
Multiple past thread posts on this topic with as many multiple solutions - screening your pellets to reduce the dust level, decrease the hoppers friction coefficient by spraying silicone lube, graphite spray, rubbing with wax paper, spraying with Protect-All carnuba wax spray (this worked well in my stove and seemed to last the longest) or treating the hopper with other various wax compounds, foil taping the seams, are all things that have been used with success.
RE your Castile heat output. Being on the lower end of the BTU output side, (especially for those of us with the older model Castile that only have 8 heat exchanger tubes instead of the current 10 tube design), several of the 'consummate Quad tinkerers' on this forum who have that stove model, ie tj, B-mod, Swine flue, among others, have come up with some simple and inexpensive modifications to increase the BTU output of these stoves.
Search "Quad mods" for multiple postings on this topic - here's a link to one of the best threads that tj initiated, following his excellent evidence based research, and 'sparked up' a lively discussion.
https://www.hearth.com/talk/threads/64123/ After doing all the various mods on my stove, except for the exchanger tube 'turbulators', which I just haven't gotten around to doing yet, they have both increased my stoves heat output and performance while also reducing my over-all pellet consumption.
As in any stove modification, it can void your warranty and / or have the potential to heat stress your stove components, ie they are not Quadra-Fire nor home owners insurance company sanctioned. But many Quad owners have used these stove modifications with excellent success, with no adverse stove effects, *to date*.
Standard disclaimer / assumption of risk applies: 'YMMV', and 'use at your own risk'.