You may want to upgrade the power plant and power distributor first.
This is my usual trading/combat loadout:
http://www.edshipyard.com/#/L=60g,0...7u57u5,2-7_7_7_6u6Q7_8I,0AA7Sk05U05U05U03w2UI
92T cargo space and a 23.16LY fully laden and fully fuelled jump range.
All weapons on one fire-group, beams on primary fire, multi-cannons on secondary fire.
I've found 4x small beams plus 2x medium multi-cannons are better than 4x small multi-cannons and 2x medium beams. It may be different if using fixed weapons instead of gimballed.
Advanced discovery scanner is there to get exploration credits when jumping into an uninhabited system on route. This is on fire-group 2, secondary fire.
I never bothered with a military spec. hull because once shields are down in combat I usually keep my distance and recharge. I might try a military hull sometime and see for myself if it makes any difference. It would take a bit of a chunk out of jump range but I may be able to live with that.
For exploration:
http://www.edshipyard.com/#/L=60g,0...4yG4yG,2-7_8S7_6u6u8S8I,52W7Sk0KU0KU05U2jw2UI
AFM's go on priority 3 to shut down if hardpoints are deployed. I've realised, after only one deep space exploration trip, weapons are not necessary (but peace of mind is a good thing) so next time I may drop the weapons and use a lighter shield generator. Also I might replace a couple of heat sink launchers with point defence for front and rear utility mounts (they're lighter and may come in handy if, without weapons, I have to run instead of fight back). Also drop the 8T cargo bay and stick another AFM in there. Maybe a more expensive fuel scoop - 6D or 6C is more than adequate though. 6A is just ridiculously expensive and justs adds to the rebuy cost.
Something like this:
http://www.edshipyard.com/#/L=60g,0mI0Wg0Wg0mI,2-7_8S7_6u6u8S8I,52M7TC0KU0KU0KU2jw2UI
I'll be keeping the 'A' rated power plant though because they run coolest. No point dropping to a 'D' rating for an extra 0.17LY jump range.