The entire point of this CRT was to allow Goku's resistance here on his LS profile and those who would scale to him. Whether it was accepted as a black hole or not.
There are 3 ways this feat can be calced
1) Simple comparative gravity analysis. Only the gravity itself is compared, it's created gravity is strong enough to prevent light from escaping, which means it's escape velocity is above LS, neutron stars have an escape velocity at half of this. It's gravity is stronger than any known thing not called a black hole. If Goku resisted that gravity, then he's handle one of a neutron star much easier. No assumptions or mass or density calculations needed. Simply put, if gravity A>gravity B, then anyone who can handle gravity A can handle gravity B easier.
2) Using the 'Vesc = SQRT(2GM/r)" to get its mass using SOL or 99% SOL(as low end) or 18's blast (at high end) as it's escape velocity and the calculated radius, and then using the g=GM/r^2, to get the acceleration due to gravity, I'll Confirm if this formula is applicable. Again, no assumptions needed, radius can be extrapolated, G is a constant, escape velocity is a lowballed SOL or 99% SOL, OR 18's blast - depending on if ftl values can be used in the formula
3) Using the compression force like
@CloverDragon03 suggested, I saw the initial attempt, and requires some assumption like the density used, did come out at 1.55e+11kg tho