Aye, i'm not surprised, you have a slightly gimped setup there matey, but nothing to worry about, only some slight tweaks.
You can chose to use 220 or 425s, i think a lot of ppl use 220 because it has better tracking, bearing that in mind you wont need istab or really the nano. Also dump your shield extenders to reduce your sig to increase your evasive defense, and ditch your pdus you don't need them.
Armour tank your vaga with a 1 x small and 1 x medium rep, have the small on when you start taking dmg. Put on a passive exp and kin armour hardner for your lowest resists, and then put on a damage control II, have that running constantly. Just actually noticed that vaga has 1337 base armour points, lol.
In your mids: disrup2, webber2, AB2, tracking disrup2. You don't want mwd really, the vaga doesn't need it and tbh it needs cap more and less sig. I think you might have enough power for a nosferatu2, but i'm not sure cba to calculate it. I think the reason your friend got to you was because of the mwd mainly, since it increases your sig radius 500% making u larger than battleship size to his guns. Also going so fast in a orbit means you exceed your gun's tracking capability, ok so he has the same problem, but he's got a bigger target to hit than you, so he has the clear advantage. Remember also that your twin shield extenders also played a big part in increasing your sig size even more.
Since this is a 1v1 you won't need a gyro since the stabber who you're fighting won't have very good resists anyway, plus also you're messing with his tracking. If you find your guns aren't hitting that well, slow your orbit down.
No doubt someone will correct me if i've made a mistake, much appreicated. But i hope this helps or gives you a rough idea anyway, and hopefully u can beat-up your friend and convince him to get a vaga too, lol.