Yea...I agree. The stand is over kill, the transmission is really high and I don't see how you'll do it without raising the back wheels way off the ground, or use a hoist as mentioned.
Also, how do you plan on supporting the transmission while you remove the cart ? There's no way to install the transmission mount/crossmember
The cart I used doesn't support the transmission at all, so once I bolt the K frame back in, I slip a jack under the transmission, raise it slightly and bolt up the crossmember.
I just hook my engine hoist inside to the frame....no angle iron needed. I've done dozens of cars this way since 1993.