I have done it both ways, and prefer to roll the rear end back rather than pull the engine. Because of steep dangle-angle to pull the engine out of a '41 with the transmission attached, you have to take the hood off. An then there is the pain of exhaust pipes and chatter rods to deal with. The rear springs on the '41 bolt directly to the bottom of the cross member, but the U bolts can only be pushed up about half way, so you have to get the rear of the car jacked up pretty far for the spring to clear the U bolts. You should disconnect the speedometer turtle, but you can leave the brake hose connected. That leaves the shock dog bones as the remaining link. You might be able to force the rear to roll back far enough with them still attached, but I disconnected one end. The shock link removal tool is about $50, but well worth it.
Once the rear is rolled back enough to disconnect the U joint from the rear of the transmission, block the front of the torque tube down as far as you can, because the rear of the transmission is going to have to come back over it, and you can only jack up the rear of the engine so far, due to the bell housing hitting the firewall. Disconnect the clutch actuator bar and remove the top transmission bolts before jacking up the engine. I suggest two strong young lads to slide the transmission back and lift it out of the floor. Removing the seat makes it easier, but is not necessary.
Given what a pain it is either way, be sure the clutch disk, pressure plate, pilot bearing and throwout bearing are in good shape before putting the transmission back in, If the transmission is wiggled in removing it, the clutch disk can get misaligned with the pilot bearing, so check said alignment before putting the ****** back in. Use an old transmission front shaft, or they sell a clutch alignment tool. Nothing more frustrating than fighting to get the 80 lb transmission lined up and having it refuse to go forward that last inch.
With the transmission in neutral, it is usually not too hard to get the U joint to slip on. It takes one person at the rear, rolling the rear forward, and one at the front aligning the joint to the shaft. Watch your fingers!
Have fun!