Cardboard on the BD head might be a good idea, but I think the rest would be ok without it.

Make sure floor tom legs don't protrude past whichever rim sits on the bass drumhead.

It's been awhile since I've had to stack, but I put some 2x4s on the bass drum and stack the toms on those. Mine are long enough for the snare to stand alone. Then plywood between each tom. It's still not an ideal system, but at least the hoops and rims are bearing the weight instead of the heads ... the heads are probably still bearing some weight, but not directly.

The heads may and probably will become cosmetically damaged over time. Clear heads can develop abrasions where the rims are resting on them and coated heads can begin to stick to the rims of adjacent drums. A piece of cardboard or a cloth between toms is a simple solution. Keep in mind to protect the snares and snare head. I see guys stack their snares, right side up, on top of 12" or 13" toms all the time. Why? I have no idea....

I would also come up with a way to not stack directly on the bass drum head with 1x or 2x stock or possibly plywood.

Using those few tips you will be just fine. The weight of a few toms is nothing compared to the shock load drums receive all the time while in use.

I stack mine in the garage on shelving I installed. The bass drum sits upright with the head facing forward. The toms are stacked one on top of the other next to the bass drum. All my kits are 4 piece kits so it's only one tom stacked on the floor tom. Because I installed I set the spacing to accommodate 20" bass drums on top and 26" bass drums on the lower shelf. Hope that helps.

All of mine stay in the house.

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