I feel your pain and suffer the same frustrating problem. In a split second my riding buddies are gone (with their Rekluse equiped e-start 4 strokes) and if the bike doesn't start right up or I'm tired or in an awkward position it really adds up. Anyone who rides crazy technical terrain for miles on end and and can't see the benefit of an e-start 2 stroke is beyond me.
So a few thoughts
Live with it and get better at riding
This is obvious for sure. The better shape I'm in the more focused I can stay over a longer period of time and remain in that aggressive enough mode to always be ready to slip the clutch. At 52YO I'm on a mission this year to be in the best shape I have been in years. Dirt bike riding and racing, mtn. biking, road biking, trail running and some weight training should do the trick I hope and eating better with more sleep as well.
Buy a 250
Another possible solution that seems to work for many people. I'm still mixed on the 300 and it's power delivery and may also go this route. Still on my KTM 250 EXC with it's mellow electric motor I still stall the freaking thing to much, even with soft organic pads. I have a Rekluse Pro to install into this bike so that will be solved soon enough
Remove the high volume PV chamber I have
The 300 doesn't need the high volume PV cover IMO. This is easy, just install the stock cover and see how you like it. No cost at all.
Change the jetting
Fat jetting or straight taper needle helps smooth power delivery but not sure it will help your stall problems.
Buy a Rekluse (the pro's not available though I woulddn't pay for a new z start and the EXP sounds like it is for MX and doesn't have the adjustability...)
This is the route I'm going to with the Gasser (EXP) I look at it this way, the EXP will be very similar in action and performance to your regular clutch with the added advantage of anti stall. I'm hoping it will have a little more slip than a standard clutch (which I think it will with the light wedges installed) but the fact that it acts and feels like a regular clutch, has full over ride capability, and wont stall is good enough for me. I'm sure as Rekluse tinkers with this newer EXP it will get even better.
Any other thoughts.
The biggie I really think is being in better shape so you can stay sharp and focused longer. I know, easier said than done. I've resorted to riding my 250 different and letting the motor scream more as much as possible before shifting up but I can get away with that because it mellow and electric in its delivery for the most part. The 300 not so much. When I'm caught a gear to high always have my hand on the clutch....but it doesn't always work
Have you tried the G2 throttle cam system?
EDIT...HuskyDude mentioned a heavier FWW which might be a good option to try. What ignition does your bike have now 2K2 or 2K3?