Chris , don't worry mate your 100Ed at f9 is in the APO territory easily , nice scopes these. Not everybody can afford a 4-6K Astro Physics , Takakashi , TEC . etc , etc , your scope will produce very good results ,,, once you learn how its done , good luck .
On the guiding have you looked at the 'Orion' 50mm guider packages for sale at Bintel , these work very well from what I have seen .
Brian.