I also plan to get myself a Hornet .. I bought my first bike exactly 1 week ago.
I bought a brand new Honda cbf125. I asked them to sell me a restricted hornet until I pass my DAS -- and the Honda garage refused to sell me the thing ('If I sell you one of those with your (lack of) experience, even restricted, I'll be reading about you in the local paper in a week!!!!')
I also plan to keep the 125 for 3-6 months then do the other test. Wow, are you my dopplar twin? After 3 months apparently you're hungry for more power (don't feel it at the moment!). Also much longer on th 125 and you teach yourself bad habits which have to be 'unprogrammed' when preparing for the DAS - so paradoxically it makes it HARDER to get the DAS if you've been on the CBT for a long time!
OK -- some advice from a noob in exactly your situation. in fact, unnervingly exactly!
1) If you can already drive cars and have done for a while .. take the theory test now. Don't bother revising. You'll pass it very, very easily.
2) Do not feel you HAVE to do what the other bikers are doing with regards to overtaking and filtering. I spent the first 3 days behaving exactly like a car. Sure, you don't shave any time off your journey -- but honestly -- until you're more confident .. sticking in traffic is fine.
3) If the bike conks out, then it seems like the battery is dead because the starter motor won't fire -- the problem is simply that you've forgotten to change it back into neutral so the bike is 'protecting itself' by not letting you start it in gear. Don't call the garage and get them to come round to 'fix' it, then get all embarressed as they kick it into neutral and just start it up!!! That would be aweful. And yes, I did precisely that. And yes, they laughed at me!
4) TURN OFF YOUR BLIMIN INDICATORS once you've done your manouver! And learn how to fill up with petrol before you're very low - ideally at home (obviously no petrol there but use your imagination!) -- so no-one watches you (again very embarrassing) spending 10 minutes trying to figure a way to carry your helmet, gloves, wallet, keys AND filler cap simultaneously, and continually dropping one/two of the aforementioned items!!
5) I have been riding for 1 week and already checking my blind spot has saved me once -- from side-slamming a cyclist. When you're changing lane or turning (involving leaving your lane) I can not emphasize enough to check your blind spot. If you stop bothering, sooner or later you will wake up in hospital with a punctured lung and 7 fractured ribs .. or maybe not wake up at all
Thats all for the moment. I've got exactly the same plans as you and am at the same stage of my riding career (well, 1 week in front of you) -- so I can advise from the perspective of a brand new biker. If there's any further way I can help ...?