I fly the Guardian in RR fleets as well as solo to support armor tanking mission runners. However I also have Logistics V now and that makes a huge difference. I do not have much experience fighting sleepers however the following fit is solid and battle tested quite a few times. Works for Logistics skill IV and without Logi IV you should stay away from any logi cruiser. Some would say the same without Logi V, but I am not quite that prejudicial.

800mm Reinforced Rolled Tungsten Plates I
Amarr Navy Energized Adaptive Nano Membrane
Damage Control II
Amarr Navy Armor Thermic Hardener
Amarr Navy Energized Adaptive Nano Membrane

10MN Afterburner II
Conjunctive Radar ECCM Scanning Array I

4 x Large ‘Solace’ I Remote Bulwark Reconstruction
2 x Large ‘Regard’ I Power Projector

Medium Ancillary Current Router I
Medium Remote Repair Augmentor I

Light Armor Maintenance Bot I x5

That is a pretty pimped out version, you could most likely drop the ECCM for a mod of your choice, but it has 40k ehp, and is cap stable running the ab and all four reps as long as you have a buddy feeding you two power projectors in a dual Guardian setup. Logi V and you can drop one of the power projectors and add one more remote armor repair.

This fit is less expensive, but sacrifices 2k ehp.

800mm Reinforced Rolled Tungsten Plates I
2 x Energized Adaptive Nano Membrane II
Damage Control II
Amarr Navy Armor Thermic Hardener

10MN Afterburner II
[empty med slot]

4 x Large ‘Solace’ I Remote Bulwark Reconstruction
2 x Large ‘Regard’ I Power Projector

Medium Ancillary Current Router I
Medium Remote Repair Augmentor I

Light Armor Maintenance Bot I x5

Very low on CPU so you will likely have a hard time filling the last mid slot.

Another option is to go 1 x medium ‘regard’ and 1 x large ‘regard’ and drop the Medium ACR, you remain cap stable with another Guardian but can be a close one if neuted.

Good luck out there with the Guardian!