sitting cushions, and getting rid of that crutch

(notes of mine from many years ago)

Sitting Cushions

The goal is to get to full lotus eventually with no cushion. To get there, you will need to gradually loosen up your hips, leg muscles, back muscles. When you're free from cushions, you can meditate in many more places with no encumberance or baggage, and you can sit and meditate longer because full lotus on flat ground gives you maximum footprint and support and lowest pressure from body weight sitting.

cushions that work well

sun and moon brand crescent cushion - get the buckwheat hull model, and remove about half to 2/3 of the filling. keep it in the bag so you can adjust later. The idea is you want to adjust the cushion, fluff it so it has a gradual downward slope, and by removing a fair amount of the filling the cushion has some give to shape to your body. The factory setting is too full, so it will be hard and you'll feel it when you do long sits.
other crescent or kidney shape cushion brands work pretty well. my friend swears by the sun and moon brand because it doesn't give him numb nuts like some of the other brands do.

angled seat more than 90 deg

dense foam shaped like a triangle with a gradual downward slope, about 1 to 2 inches high when supporting body weight. I haven't tried it out, but it should work similarly to the idea I did try, which is to just sit on a sheet of plywood with a couple of thin slabs of wood to elevate the slope to about 1 to 2 inches high.
folded up blanket or yoga mat to give yourself a little elevation under your butt. fleece blanket works well. Gradually decrease height of cushion till you're free at last from cushions.

If you're dependent on chairs and sitting cushions, 

it makes it harder to do this:

 (STED 16-APS 🌬️😤)

[0.1] 🏞️ arañña-gato vā	[0.1] 🏞️ (to the) wilderness-(he)-went, or
🌲 rukkha-mūla-gato vā	🌲 (to the) tree-root-(he)-went, or
🏕️ suññā-(a)gāra-gato vā	🏕️ (to the) empty-dwelling-(he)-went, **
[0.2] nisīdati	[0.2] sits down
[0.3] 🧘 pallaṅkaṃ ābhujitvā	[0.3] 🧘 (into)-cross-leg-posture (he)-bends,
[0.4] 🏃📐 ujuṃ kāyaṃ paṇidhāya	[0.4] 🏃📐 straightened body (he)-aspires (to),
[0.5] 🌬️😤 pari-mukhaṃ satiṃ upaṭṭhapetvā.	[0.5] 🌬️😤 Near-(the)-mouth, remembrance he-establishes.
[0.6] 🐘 So sato-va assasati,	[0.6] 🐘 He, Always-a-rememberer, breathes in;
Sato-va passasati	Always-a-rememberer, breathes out.