4th & 5th axis basics?

[Donkey Hotey]

I think it's time I try my hand at 5 axis.

I've searched the archive for over an hour. Despite learning a lot of useful information, I'm not fully ready.

I have a 2004 VF-2 and a T5C indexer (the HA5C mounted to the HRT210 rotary). The VF-2 has factory 4th axis and I have a Haas Servo control for the remaining axis.

I've got some questions I need to resolve in my brain before I figure out the best way to use this equipment. A number of recent jobs involved round parts, held in a 5C closer and turned for multiple setups. It's time to put the T5C to work.

1. When I enable the 4th axis in the Haas control, it will address the connector on the cabinet as the 'A axis'. If the remaining axis is connected to the Servo control using a serial cable back to the machine, how is that axis addressed? B-axis? Or do I have to address it by M-codes? I know I'm only going to get semi-5th but I'm unsure how to address it in a program.
2. What do people generally use for an origin? The intersection of the two rotary axes?
3. If I'm using it for semi-5th, I'd like to just do all of the positioning with work offsets. I know the control can have 4 axes as work offsets but I'm still unclear as to what happens to the 5th axis if it's controlled by the outboard box. Do I get work offset values for all 5 axes?
4. Any other stern cautions or warnings?

[PBMW]

I think your VF2 will do 4 plus 5th positioning.
Think is terms of tool vector.
Set it up in your cam system. Program from center of rotation....

[CNCRim]

You Haas positioning address should be A B or C.
A30., B20.,C-20. etc