from your vehicle useage and RPM power range, the cams that operate in your power band would be something like the comp XE268 or XE274. The XE284 is pretty large and on the simulator it looks like it will only make a bit more power above 5,000 RPM (the heads start being the restriction), but give up 20-30 ft/lbs torque through the entire lower RPM range up to about 4,000 RPM.

The Launiti Voodoo 60403 and 60404 also look good.
Also, the Hughes Engines HEH2832AL would work too.

once the compression ratio is ironed out it may help narrow the cam selection. The smaller cams would work good with slightly lower compression ratios, but could cause too high cylinder pressures with higher compression ratios, so if the head/piston combination has a higher compression ratio (I am thinking 10:1), then the larger sized can would help bleed off some low RPM cylinder pressure (Later Intake closing point plus more overlap.)

Depending on your cylinder head volume (62cc?), gasket volume (9cc?) the KB-107 piston should be about 10.53:1 compression, which may work ok with the larger cams. The SpeedPro ZH116CP piston is slightly shorter (compression height) and it would have about 10.17:1 compression ratio.
I looked at the speed pro ZH405 pistons, but the compression ratios were pretty low, around 8.9:1 compression ratio. The KB-190's are domed pistons and about 11.35:1 compression which would be too high for pump gas using the iron heads and the cams noted above.

Right now, I am starting to like the looks of the Hughes HEH2832AL with the ZH116CP pistons, but the Voodoo 60404 with either the ZH116CP or KB107 pistons also looks like it may work too, but I am concerned about the higher compression ratios of the 107 pistons...