hi Rodney,
I hope others will comment as well, I just wanted you to have all the facts clear before you spent your money.
Can you tell why you want to get the filter wheel and LRGB and Ha filters for the Canon 600d?
An unmodded dslr has an IR block glass in front of the sensor that blocks a significant part of the red spectrum. it also has a bayer matrix on the sensor that essentially has red, green, blue filters above each pixel.
so red light will only go through the pixels that have the red filter, blue through the blue and green through the green.
so of the 18million pixels on your sensor, only 1/4th will allow red, 1/4th allow blue and remaining green as the pixels are usually arranged in an RGGB square.
this should explain it.
http://en.wikipedia.org/wiki/Bayer_filter
therefore, using an LRGB filter will not give you true LRGB images as you'll have to extract each colour plane, that is separate RGB and then discard the rest. you'll be wasting a lot of time and effort this way.
LRGB filters are really designed for mono sensors.
same with the Ha filter. An unmodded dslr will block a lot of the Ha signal and since your dslr has a bayer matrix, you'll have to discard the G and B channels and the 18MP would drop down to 4.5MP as you can only use the R plane.
so you'll need to expose for a very long period to get any significant data and that introduces noise as your dslr is not cooled.
finally, the spacing.
most coma correctors need to have a very specific distance to the sensor.
the Baader mpcc which is a very common and effective corrector, requires 55mm to the sensor.
the dslr sensor to body is 45 mm so you're left with only 10mm. that will normally be taken up by the bayonet to T2 adaptor. so if you screw the coma corrector to the T adaptor, the distance would be perfect and you will have no coma and can use the full image FOV.
if you use a filter wheel, the distance becomes much more than 55mm and the corrector won't work.
you do have the option of using a rowe coma corrector or others that allow more than 55mm of back focus, but what i'm trying to advise is that the filter wheel with the dslr is very ineffective.
just trying to save you a lot of heartache as I've been down the road as well.
my suggestion.
get a coma corrector, and since you already have guiding, you can get some really good results with galaxies and nebulae even with an unmodded dslr.
then when you're ready for mono imaging, invest in a 2inch motorized 5 position wheel and an off axis guider with a cooled ccd. you need the 2inch as the light cone of your 10inch F3.9 is steep and you'll have vignetting.
so before you get into mono, experiment with the dslr and coma corrector.
I'd suggest you invest in a light pollution filter as well. the IDAS LPS P2 is a very good one and others tend to alter the colours a lot.
hope I've clarified things, I'm surprised that the vendor did not tell you all this.
any questions, just fire away. there are plenty more experienced members here glad to answer.
Cheers
Alistair