An additional 3 to 3.3 grams can be added to the eight ounce gel (as for the other Avant 8 ounce hormonal gels this holds true, too. For the four ounce ONE, an additional 4.5 grams of so can be added).
Tren can be added within light of the afore mentioned numbers; however 1-Test and Tren qualitatively deliver much the same in lean muscular accrual (not to mention that both pummel the libido) so this is not the best of combinations (a Tren/4ADerm stack would be better, considering what was said).
But, that is a matter of your choosing; one can also purchase the carrier Gel separately, as well (to carry the Tren, if one does not with to add it to 4AD).