If you intend to keep a 235/85R16 spare tire in the stock location you may need to make some modifications to the sheet metal in order for it to fit depending on which 235/85R16 tire you put back there. I was not able to fit an original tread pattern Goodyear MTR 235/85R16 in the stock location, even deflated. It may also not be entirely feasible with a full width drawer system. Depending on the preferred layout of the drawer system, the placement of the spare tire may need to be rethought.
Not desiring any type of drawer system, I have modified my 1991 RRC Hunter to fit a new 255/85R16 BFG KM2 tire. Because of this tire's 33+" size when new, I believe this is the largest possible tire to fit in the original spare tire location and doing so does have some trade-offs.
I didn't want decreased visibility of a rear tire carrier inherently causes. I also didn't want the weight dynamic of the vehicle to change by as much as an exterior rear tire carrier/custom bumper/and 33" spare tire attached to the back would cause. I also didn't want to lose the cargo space inside on the floor as I had previously experienced with 235/85 and 255/85 size spare tires located there. Thus, that meant modifying the interior sheet metal to make the tire fit inside in the stock location.
So the sheet metal was cut out and new custom pieces welded back in place to accommodate the 255/85. But there were trade offs for this scenario.
1. Rear driver side seat belt originally mounted above the spare in the stock location occupied space needed for the spare tire and thus has to be removed. This wasn't a concern for me though as I have only had more than one passenger ever in the vehicle only a few times and the seat was removed and an ARB refrigerator put in its place. So I didn't need the seatbelt at that point.
2. Rear driver side bump stop had to be extended even lower as to prevent the 255/85 rear driver side tire from making contact with the newly modified sheet metal that now occupies part of the wheel well. We did figure that one out after the fact.
3. It eliminated the possibility of installing a full width drawer system as the 255/85 tire would not be able to be lifted above a drawer system that is taller than 6". Assuming loss of 2" for top and bottom materials and sliders, gives you a workable drawer height of about 4" which seemed to me kind of pointless. Also, with the 255/85 in order to remove the spare from the stock location I have to tilt it out into the cargo area and do very little if any actual lifting of the spare tire. What gets in the way of lifting the spare? The roof, the wheel well and the D pillar. Hence why I believe the 255/85 is the largest spare tire possible to put in that location even with extensive modifications.
4. Have a stock dog guard in your RRC? Plan to move it or remove it. Space is severely limited since the stock dog guards extend below the rear seat backs. Placement became dictated by the spare tire as it forced the dog guard to move forward but forward movement was quickly halted by the rear seat backs. I have about 1-2 millimeter gaps between the spare, the dog guard and the rear of the back seats.
See photos below. Larger photos and an additional details can be found here
http://azlro.org/chad/spare.html.