We've been shiping this peptide into the US and EU for a while now, and most buyers go with the 1g minimum because of that it hits sweet spot between cost and flexibility.
The CAS is 129954-34-3, and that holds up well at -20°C for about 24 months or so, though I'd recommend using it within 6 months once reconstituted.

Purity runs ≥99% by HPLC, which is better than reagent grade for this kind of work, and we usually have stock ready to go — but confirm lead time for larger orders, especially if you're in the UK.

Import docs are straightforward, our company provide COAs with every batch, and customs in teh US and EU typically clear it without fuss since it's clearly labeled for research only.

One thing we've learned is that the 5L drum is easier to handle than the smaller vials if you're running multiple assays, but the sealed vials work fine for single studies.
It's basically not suited for anything beyond in vitro work, so don't expect it to perform in vivo without proper formulation.