I'm not sure I'll be able to give a good evaluation of the Stage 4 plan before your shmupmeet, but I'll try to finish up the "Clear Stage 3" plan at least.
I believe you can hit the 10-million-point extend and procure the 1-up item found in Stage 3. Plus 2 bomb pickups (before Stage 2 boss, at body before 1-up head in Stage 3). 17 bombs to allocate.
The "Clear Stage 3" plan [version 1] has 20 bombs, which assumed the 25-million-point extend as covered in your topic post. 4 boss-related bombs can be removed from the distribution (mirroring the two boss strategies in the "Clear Stage 2" plan), giving 16 mapped with 1 unmapped.
For the Stage 3 boss, you can bomb into C and A+ point-blanking 3 times for the first form (the three bombs listed there now), but the second form only needs two bombs with this effective, if inelegant maneuver. The bomb location "2-2 madness" can be removed as the boss should explode before it fires this pattern if you bomb+C&A+ point-blank its second form.
Quick note on the point-blanking: for the first form, you'll want to sit on top of the boss
while the bomb aura exists only. The boss is on the same plane as you, so you can collide with it, but it has small turrets at its bottom which will soak up many of your bullets if you don't position yourself above them/directly on top of the boss. For the second form, you can shoot it from very close below--you don't need to place your ship on top of it.
You don't need to wait out any of the bomb auras before launching another bomb on this boss, though some patience in this regard will help prevent stray bullets at the form change.
15 bombs mapped, 2 unmapped.
For these two remaining bombs, I suggest:
- An extra bomb at the 3-way spaghetti spreads as proactive security--depending on your route through this area, you may find another bomb helpful.
- A bomb between the two shoulderblade areas as the background moves to the right/player moves to the left shoulderblade. There are two larger enemies and many popcorn enemies that will fill this area with bullets. A bomb will do nicely to mop up some of the extra fire.
It is possible to do the Stage 3 boss with fewer bombs--I've done it with only 3 several times--but using 5 should be the very safe way to do it.
If you want a little more challenge, the second form can be done with only one bomb or none at all.
The "2-1 tap-tap the even-odd-even-odd etc" pattern fires in what I count as three small waves. First with only the guidelines (no even-odd). Second with guidelines and loose even-odd. Even when the guidelines fade, the even-odd remain to transition into... Third (final) guidelines+faster/tighter even-odd.
Second form, zero bombs (assuming C and A+ combo for duration): For the first wave, get as close and you can safely.
For the second and third, drop several (3?) ship-lengths down the screen to give yourself time to read the even-odd spreads so you can react to them. When the final spread clears, close the distance to the boss. It will start its "2-2 madness" attack. As the bullets come close, lower down the screen to compensate. The boss should explode before this pattern becomes a problem.
For one bomb on the second form, dodge the first two waves of 2-1. Bomb at or just before the transition to the third wave, point-blank.
I've also been experimenting with a way to reduce the first form to 2 bombs, but it isn't 100% yet and will be difficult to describe--I don't expect to have this finished soon.
Again, the 5-bomb point-blanking is the safest way through and the one I recommend for the "Clear Stage 3" plan.