I have No doubt it was heavy! I've had to replace mine twice in our 99. I remember the first time having to pull it out and it was stuck! With 15 gallons in it still. Really tight place on those. There bigger than they look lol. I Wonder if a person could swap in a Tahoe tank and put the spare in its place?
Good question, I will have to ask on the 400 group. I personally like the extra range that tank gives, versus the newer SUVs that have the spare downstairs. I've personally had more trouble getting the spares down on the vehicles that had that mounting, than buying the extra gas.....
As long as you have a good jack and a charged up impact gun (or at least a good lug wrench!) the spare is accessible in the rear cargo area of the Burb (because I put things in front of it that can be easily moved without disturbing the rest of the load). But if you need that extra 100 miles of range from the extra 10-15 gallons in the tank(that you don't have because the tank ain't that big) you're kinda screwed.
The last couple of times we went to Lafayette, Louisiana, for a car show there, from Houston, Texas, we went in my Burb. 42 gallons tank vs. 31 gallons in the '06 Yukon XL Denali that we'd made the trip 3 times before. With the Denali we'd have to gas up before leaving Lafayette, to be sure we could get home. Or if not there, definitely before leaving LA. With the Burb, even towing a trailer, that extra 11 gallons would get us most of the way home. Gassed up in Beaumont or Baytown....I have a friend who used to have an '08 Yukon XL Denali, also with the 6.0; several friends from our model car club went to Lake Charles in it, pulling a heavy trailer, and we had to gas up on both legs of the trip. Of course he or his daughter was flogging the 6.0 for all it would do with the load and 5 of us in the truck, that did not help the mileage!