I am able to source a crazy jet for about 1/2 the price of a laylax... so if performance/quality is close enough, I am willing to settle for the crazy jet (unless your experience tells me crazy jet is a horrible choice)

Second question is I am torn between a 303mm vs a 430mm ... i prefer the mobility with the 303mm in my g-spec, but dont know how much difference in performance can I expect between the two lengths?

All comes down to muzzle energy.
Theres no difference in range or accuracy, just your maximum muzzle energy

If that's the case, I would prefer the 303mm... this is for a HPA/Co2 setup though, would the length matter?

You can just up the pressure if you need more power, so 303 is fine.

Awesome! Thanks for the advice ThunderCactus!

Actually have a follow-up question regarding the barrel length...

If I am using heavier BBs (0.4g or +), does longer barrel make more sense in accelerating the BB which should increase range/accuracy, and I guess conserve air as a side benefit? Or is this flawed?

instead of spring cocking, you might want to check out wolverine airsoft's BOLT and Wraith co2 conversion
https://ampedairsoft.com/wolverine-a...use-with-bolt/

Short answer, yes it will give you more length and time to accelerate heavy BBs
Longer answer, you should be able to get to 2j pretty darn easily with a 303mm barrel and an hpa rig
Longer still, if youre getting too much power at desired settings on long barrel, you can cut it down