Got the chance to get things going.

Decided to try the 3/10 ratio at 100mg/mL:
0.3 mL BA
1 mL BB
1g MENT powder
7.85mL* of GSO
*Based on 1g = 0.85mL displacement

Except, I did double that. Just wanted more stuff in the vials at once for brewing. So the end result is still 100mg/mL at 3/10% but I'm doing 20mL total.

Procedure:
1. Bring shallow pot of water to a boil. Remove from heat.
2. Place GSO in glass vial (beaker, jar, whatever) and place unsealed and not submerged in water. Deep enough to get the GSO heated. Also, I did more GSO than needed, simply because its cheap and I was going to pull the required volume from the heated vial. So, roughly 50mL or so.
3. While GSO is warming, place Trest powder, BA and BB in another glass container. Swirl around as best you can. This container is for the mixing.
4. Once GSO is warm/hot (after 5 minutes or so), draw out necessary volume and add it to the Trest/BA/BB solution. Discard remaining GSO from hot water.
5. Swirl/lightly shake new solution to dissolve as much Trest as possible. Place glass container of Trest/BA/BB/GSO in hot water. If needed, water can be reheated, WITHOUT GLASS VIAL IN WATER. You don't want to heat the water with the glass container in it. There is no need to get the solution too hot.

To be continued...

After doing the above, you can still see some undissolved bits that settle to the bottom. So far, about 85-90% of the powder has dissolved, so I'm going to let it sit overnight and see how it did in the morning. I had the same issue when making Tren from Fina a couple years back. Everything dissolved overnight, so we'll see what happens.