Yes you should send another disclosure request for a typed copy of the notes as they are illegible as is. And I would also request the following pages from the manual: Operating Modes, Testing The Device, Specification, and Legal Requirements. Make sure you say something like "I require these sections of the manual in order to properly prepare my defense and be able to properly cross-examine the officer."
Maybe if you get them 1 week before you will feel okay going forward on the trial date, but that will really be up to you. I would suggest that you need at least 2 to 3 weeks to properly prepare your defense so I would personally ask for an adjournment. If you do ask for an adjournment, make sure you request that the time count against the prosecution in the event you need to file a motion for lack of speedy trial in the future. In your request you asked for typed copy, so this should have been provided initially. The JP will most likely agree to the adjopurnment, but if the JP makes you sit down with Officer to review the notes and will not give you an adjournment and forces trial to go forward that day, then this would be good news because you would almost certainly win on an appeal.
The best way to challenge all radar devices is usually the testing procedure and also the officers knowlege of its use and their training. The courts have decided though that an officer simply testifying that they are trained on the device is sufficient proof that they are trained how to use it properly. So good cross-examination on exactly how they tested versus it versus exactly what the manual says is important.
As far as the GHD Scout specifically is concerned, read this thread http://www.ontariohighwaytrafficact.com/topic7284.html and download the attached pdf and scroll down to the Notice of Motion to exclude all radar evidence. There are also some good cross-examination questions in there as well.
Since the officer already reduced the speed, there is close to a 0% chance the prosecutor will offer to reduce it more. It does not hurt to ask of course, and maybe the prosecutor is in a good mood and offers you 15 over instead, but remember even a 0 demerit point charge can cause your insurance to go up, so demerit points are irrelevent. Also remember if you go to trial, they will amend the charge back up to the higher original speed at the trial so you will be fighting the 38 over charge.