I picked a barely used 550B with bullet tray, roller handle and strong mount locally for $600. Maybe it would have been nice with the auto indexing... I don't know but I only load 9mm and if everything runs smoothly I can pump out 100 rds in about 20mins... I take my time and weight a charge about every 30 rds for accuracy. It goes up to about 30mins for a 100rds if a case does not de prime properly and the old used primer gets reseated agian. Dillion claims 400 - 600 per hour....
My setup is with RCBS and a RCBS Lock Out Die. 1 - size, deprime and prime. 2 - drop the powder and bell. 3 - Powder check lock out die. 4 - Bullet seater and crimp (if you want to)
I hear and read the Hornady LNL is at the same price point as the 550B, reloads well, has 5 stages and is auto indexing.
I thought to myself "this guy is as slow as molasses in January" then I read that you are using a lockout die in station 3 instead of seating, well no wonder.
I too was worried about a missed or double charge of powder and drilled a small hole in the middle of the tool head and put an LED light in it. That way the light is bright enough to shine down into the case at station 2 and from where I sit reloading I can easily see into the case.
So you must run the ram up on station 3 to check the powder and bring it down then put the bullet and rotate instead of rotate out of 2 put the bullet and then seat as normal.
For best pricing on Dillon stuff I always watch castbullets web site and a guy on there by the name of parrott1969 always has a yearly sale on in about Oct or Nov. He only charges 5 bucks over his wholesale cost and ships USPS to the door.
So I bought a 550 with 4 conversion kits, 6 tool heads, spare parts kit, 4 extra large and small primer tubes and 6 powder dies and shipped to by door it cost 654.00 plus 37.70 for duty.