A lot of good advice so far, to which I have little (but yes, a little) to add. For one thing, several people have told you to learn what the letters and numbers mean, and the importance of your weight and balance. I won't assume that you don't already know these things. If, however, the others are right that you don't, then I strongly recommend staying in the low or mid power realm for a while longer while you learn. The mistakes are cheaper and less potentially dangerous. Getting HPR certification is not about (grunt-grunt-grunt) More Power. It's about proving you know the ropes, so you can handle more power. (Well, more impulse.)
It really just depends on if the rocket can withstand a motor strong enough to accelerate it past transonic.
And, point of information, trans-sonic lasts from about 0.8 or 0.9 mach to about 1.1 or 1.2. You want to get over mach 1.2 (or at least over 1.1) as quickly as you can. Open Rocket can help you with that.
[Some rockets] can be launched on J motors with an L1...
Correction: L1 allows H and I morots; J requires L2.
I'm going to try to get a H100 motor after I get the High Power Certification.
Assuming the H100 gives you the performance you need (others suggested it but I haven't checked) why not use it for your certification? The cert flight must be on an L1 motor, i.e. an H or I motor, which you're allowed to buy specially for the purpose.
And finally, on the subject of visibility: for visibility on the way down or in tall grass, a brightly colored, multi-colored parachute helps. A metallic finish, like aluminized mylar, can also help, especially on a sunny day. Probably that's not the visibility you were talking about, but what the heck.
(Does all that still count as "a little"?)