Rpg rules for medium combat

I'm working on a bit of a happy medium between casual combat and heavy combat, appropriately called "medium combat" and including rules for rpg'ers. If you create and customize your ship and crew you get bonuses for experiesnce. What I'll eventually have are ship frame ratings (heavy cruisers, etc) and customizable from there. For now all I have are rules for customized characters. I'll play that through and add more. Here is what I have so far...

Roll
X=3 Y=4

Course
X= 90
Y= 90

Shields
X Y
F /20 /20
A /20 /20
P /20 /20
S /20 /20

Damage
X Y
Shld Gen /20 /20
Pha/Dis /20 /20
Photons /20 /20
Sensors /20 /20
Impulse /20 /20
Warp /40 /40

Max Range= 5

Range/X
1x5
2x4
3x3
4x2
5x1

Performance Modifiers:
Captain: above 5 rating adds to dice total (6 rating adds 1, 7 rating adds 2 etc)

Science: above 5 rating adds to chance to detect without sensors (6 rating adds 1, 7 rating adds 2 etc)

Engineer: above 5 rating adds to total phaser damage (6 rating adds 1, 7 rating adds 2 etc). Above 7 rating repairs system with 1 point instead of 2.

Tactical: above 5 rating adds to damage total (6 rating adds 1, 7 rating adds 2 etc)