Well... I've got A LOT of 300-MP to burn through before I can swap powders... Back in the day (Obama ban era 2012/2013) I couldn't find any H110 for my .357 Mags, .44 Mags, & .300 BLK, and I found an 8 lbs. jug of Alliant 300-MP for like $150 + shipping & hazmat. And I couldn't turn that down, since the burn rate on it is almost identical to H110, and it was in stock. Not long after buying it, I started finding some single pounds of H110 here and there, and started buying it up, and the 300-MP sat around collecting dust (literally). I used to always load my .300 BLK with H110, but one day I remembered I had this huge jug of 300-MP in the closet, and started researching exact burn rates, etc... and found nothing. So I got curious and decided to just dive in head-first, and do my own damn load development from absolute scratch. I'm kind of crazy like that...I like wildcatting, so I'm not afraid to start from nothing and figure it out.
And at around 10gr of powder per round of subsonic .300 BLK, it will take me about 5,600 rounds before I burn through that jug. I'm definitely about 1/4 of the way there. I've been tearing it up with the .300 BLK since I got my suppressors.
I'm kind of the same, I got like couple of lbs of VV Tinstar that I originally used in both 300BLK and 308 for subsonic bolt loads. But I ended up preferring VV N330 for 300BLK Subs (faster burn rate, lower ES) and Trailboss for 308 (better case fill than TS)
So pretty much my Tinstar would be used only for light 300blk subs (175-190s) and/or super heavy subs in 308 that would exceed 100% case fill with TB like Hornady 225 bthp, SMK 230/240, etc. And at about 7gr-10 per load, 1 lbs gives you 800-1000 rounds so it'll last a long time which is not a bad thing with the current shortages. Plus at the price of match 22lr, you're almost better off with loading your own 300blk sub.
For bolt guns 300BLK subs my powder of choice would be
Sub under 135 gr - Trailboss
Sub 135-175 Tinstar
Sub 190-200 & 208 Amax - N330 but ~60K PSI with the 208s according to QL but stupid accurate and super tight ES that it is my dedicate 400m sub load for a 3moa steel.
Sub 225gr and heavier/longer - N105
For 308 Bolts
Sub 168-208gr - Trailboss
Sub 208gr and heavier - Tinstar
For 300 BLK gassers
Sub 175-240gr - N120 works all the time in pretty much all configurations, just a wee bit dirtier and louder but will give incredible accuracy and ES in the single digits with a bit of brass prep and an accurate scale. It's very similar to 1680 but way cleaner and for me, better accuracy and ES.
Sub 225gr and heavier - N110 - might not hold the last round bolt open depending on buffer weight and gas port size.
Sub 225gr and heavier with custom AGB, lightweight BCG and adjustable JP buffer - N105 -> This will most likely not cycle without quite a bit of tuning but for a dedicated subsonic upper, it'll be clean, quiet and accurate. Couple of guys on the 300blk forums are running those.
Not sure what are the American powder equivalents but I remember 1680 being dirty in subs but great for heavy supersonics like the Gold Dots 150s which group really really well. I still have a couple of lbs in my storage. 1680 will always be super reliable due to the burn rate, you could cycle heavy subs without a can at like 850 FPS.
AA#9 can be a really good choice if building a custom upper with a AGB.
The 16” barrel already makes it a bitch to keep loads subsonic, but now I’m fighting both. 
