What Dimmer can I use That looks like an OS600 but is for a GU24 Dimmable CFL

Your lamp is a three level dimmer as opposed to a 3 position switch.

The 3 level dimmer chops the voltage where as the 3 position switch powers 2 separate filaments (50, 100) inside the bulb either separately or all at once.

The 3-way bulb should not be necessary for an electronic 3 level dimmer. Any incandescent, or dimmable CFL or dimmable LED bulb should work.

There are two things coming into play here; the lamps and the dimmer(s).

First; LED and CFL type lamps that are to be used on a dimmer switch - must be identified for that use. Looks for the word dimmable on the packaging or bulb itself. These lamps are generally a little more expensive than their non-dimmable counterparts. If it does not indicate it is dimmable, then it isn't - and should not be installed on a circuit controlled by a dimmer switch.

Second; a dimmer switch that will be used to control LED and CFL bulbs (that are identified for use with a dimmer) must also be identified for use with dimmable LED and CFL bulbs. Again, these dimmer switches will be identified for this use and will cost more than those that work with standard filament type bulbs.

Lutron has dimmers for your circuit called a "C•L™ Dimmer" and supports Incandescent / Halogen, Dimmable Compact Fluorescent (CFL) and Dimmable Light Emitting Diodes (LED) type lamps. have a look here:
Lutron Maestro Dimmer and Switch Models

Also, be wary of the total load (wattage) of the lamps being controlled. If you have multiple dimmers in the same box, derating of the switch's wattage capacity (due to increased heat) will be required.

Most old dimmer switches do not work with energy saving/led bulbs, they will work fine with the old style filament bulbs, the newer dimmer switches will be compatible with energy saving bulbs and will indicate on the packaging!

Simply use regular bulbs. It sounds like it is switched electronically probably via a dimmer. If the CFL lamps are not specifically labeled dimmable they won't work. I have seen the LED lights work where the CFL lamps will not. If you want to use CFL then replace the dimmer.

Sounds like an older unit that has either a dimmer or electronic switch. You need to use dimmable CFL lamps.

The dimmer switch you select will depend on the type of bulbs you will be using. The 'original type ' of dimmer works with regular incandescent bulbs and halogen bulbs only. They cost around $15.00. Then there are dimmers for compact florescent (cfl) bulbs and LED lights that are dimmable, as well for regular light bulbs. These types of dimmers are more expensive, ranging in price form around $40.00 upwards.
Light Switches Dimmers

If you are replacing a single pole switch ( just one switch that operates lights) you'll need a single pole dimmer. If you are replacing a 3-way switch ( two switches that operate the same light) you'll need a 3-way dimmer.
Installing the dimmer is pretty straight forward. All dimmers come with installation instructions. Make sure you turn off the circuit breaker for the particular switch you are replacing.

Ok - a couple of things, first - when a dimmer is set to minimum; zero to a barely perceptible level of light output is expected. Second, fluorescent lamps have a much shorter range of dimming that the standard incandescent lamps have. It is not unusual for a fluorescent lamp to remain off until the dimmer is at or above the half way point in the dimmer's range. Third, you can not dim a fluorescent lamp or fixture unless the lamp or fixture is specifically labeled as being "dimmable". Use of a dimmer to control brightness of fluorescent lamps and fixtures that do not clearly indicate they are designed for dimming or to control the speed of motors like those in "paddle fan & light fixtures" creates a dangerous fire hazard condition. Most CFL (compact fluorescent lamps) that readily replace the screw-in incandescent type lamps and are clearly labeled as dimmable, can be used with a standard dimmer. The traditional (non-CFL) fluorescent fixtures that have a internally mounted and hard wired internal ballast need a special dimmable ballast to operate.

Good luck!

Maestro dimmers are not recommended with any CFL for pretty much the reasons you are experiencing. The electronics within the CFLs are probably not letting the power circuitry in the Maestro charge-up - and because of that, it comes as no surprise that adding an incandescent lamp solves the problem. The company makes products that are compatible in their Ariadnia/Toggler & Diva product families, but not Maestro - you just need to make sure the dimmer itself identifies itself as compatible with CFLs.

It does not matter whether you turn on the switch or the switch is motion
activated, the light does not know who turns it on.

The switch must be designed for florescent.

What do you mean by proper base, you have a single gang wall box,
that's a box inside the wall, with the electric and a switch,
The gang could be single or hold 5 switches, which ever is installed.

Most all switches fill fit into any gang box.