<VV> dreaded flex plate bolts

[cfm]

hi again, same issue revisited, I apologize in advance for any redundancy. 
I tore into the engine shrouds and removed the front shroud again to gain access to my loose flex plate bolts.
As some of you might recall, a month or so ago, I made this repair back then too. The only rookie mistake I made then was not to torque properly and lack of thread lock. Also, this car is not currently being driven daily or occasionally.
I had to come back to this issue, because after changing the oil, I started the car and ran it up to normal operating temperature. I got a little silly with revving it during this period and whammo, the problem resurfaced (rattling). I new right away what happened. So here I am back at it, only this time I want to it as right as possible. However, I am trying to understand why this may have happened again.
It was suggested recently (through VV) that I replace the bolts because the threads may be "stretched" or the bolts have just lost holding power. But as I study the amount of space I have, its unlikely I will be able to take the old ones out and replace with new. The special nut on the backside also poses a problem as if I remove said bolt, the nut will fall and then where am I. Also when I look closely at the nut, it appears to have a two tiered surface, leaving me to believe that these nuts were brazed to the mounting plate adjacent to the flex plate, is that a correct assumption?
Last, I can't seem to get my torque wrench in close enough to perform this task correctly. The only thing I can think of during is removing the fan shroud, or two, going by "feel" without torque wrench. In the shop manual, it calls out 30-40 ft. lbs.
Any tips or suggestions would be greatly appreciated.
Chris Mann
69 monza convertible 110/PG