If you like 109 nimbleness Dave, try a G2 w/o gondollas or any ord/DT. The F is still a beter turner, and maybe a little beter at accelerating out of a turn, but the G2 imo is a F on steroids (it doesn't turn as good, but still accelerates well out fo a turn, and more importantly to me in the LWA, it has a faster top speed). I have had some fun sorties in a F though, scrambling from an airfield under attack by a huge horde of enemy turn-n-burners and taking down 3-5 before getting picked (or having to land for ammo).
Regarding the cannon packages, you're probabley just naturaly picking up that the 20mm Mg151 has the best ballistics, rate of fire, and quantity of ammo for 109 cannons.
Copypasta ala Babalon from the other 109 thread:
"On the G2 and earlier, my cowls are around 175-125, and my 20mm cannon to 225-200. On the later models, my cowls are around 200 give or take and my cannons around 300-250.
The cowls are already mounted pretty close together on the nose and have great ballistics, and especially with the earlier smaller caliber cowl guns, they really only do damage at closer ranges and in a nice tight grouping. If you're shooting your cowls into a wing for more than 3 solid seconds at 200-400 yards, then start messing with your convergences, because I can vouch that the cowl guns are lethal when properly converged and used at the proper ranges in bursts.
The cannons are a totally different bird for the 109s than the cowls, other than they are placed close to the cowls on the nose. 109s feature either the 20mm MG/FF (with only 60 rounds and horrible ballistics and rate of fire
), the 20mm Mg151 (plenty of ammo with 150 or 200 rounds, best ballistics of any German 109 cannons IMO and the fastest rate of fire
), or the much feared 30mm Mk108 (only 65 rounds and a slow rate of fire, and ballisticaly it's better than a 20mm MG/FF IMO, but still pretty bad). Each handles differently, and really the best practice/feel you can get for the first time is to go in offline mode and unload them each a couple times into some drones without any cowl guns."