I run into that problem frequently. Usually with a different number, I usually have 400-500, and they have 1100-1200. I see two differences, none of your troops are honor troops, all of mine are. Mine will be 150ish silvermist, 150ish EB, some immortals, and the rest other knight orders.
You have a few of challenges, 1. You will be outnumbered during the fight, significantly. 2. The troops you have chosen, are only "ok" at melee. 3. You seem to have no melee.
Here is what I do, order a full charge then order my companions to follow me. I skirt around the edges to the enemy archer line. This does two things that you need done. 1. It stops the enemy archers from shooting your guys (eventually). 2. it splits the enemy charge line giving your archers a better numerical equation. I find you generally don't even have to get allot of kills when using this tactic, you just have to survive and attract the attention of about half of their melees (which my companions seem to be able to dispatch), and the archers (who like to shoot at my shield).
I don't know if it will work for you. You have top tier archers and that's good, the enemy only has a pool of 300 troops, that likely means most of them are not high tier and that's good. You only have Sarleon Armored Bowmen that's bad. The decider is going to be how much of the enemy melee line you can get to divert I think. WHO you are fighting could also be a factor, Empire and Fierd both have infantry with throwing weapons that can make your day very sad. I often get to lose my first sally against the empire and fierd. Then I get to wait a day or two to heal up and go again. The advantage coming over to my side through medic skills. Most of my guys didn't die during the first sally, most of his did.