I never got an answer. As of yesterday, I was told they were still researching. Bid is over... time to assume training has to be at least two days either side.

I believe it's at least one day either side.

Contract Enforcement told me to be sure 2 days either side last year.

25.C.11.f
Conflicts with blocks of R-days under this paragraph shall be handled as follows:

1. If the pilot’s recurrent training conflicts with a block of R-days but does not split that block (i.e., it does not leave an R-day(s) both before and after the recurrent training), then only the R-days in conflict with recurrent training shall be dropped as a phase-in conflict and the pilot shall remain responsible for the remaining R-days.
2. If the pilot’s recurrent training splits a block of R-days, then the entire block shall be dropped as a phase-in conflict and the pilot shall not be responsible for any of the R-days in that block.
   

It's been a while, but I believe I have first hand experience with leaving just one R-day on one side of training and it dropped the entire block. The above contract excerpt from the 2011 CBA seems to support that as well. Maybe CE is playing CYA with their advice but the old contract appears to be pretty clear on this (at least until the TBD date).

Adler,
I know, I know I am just relaying what C.E. told me last year. The reason I even asked is someone who does this every cycle told me you had to be sure 2 days on either side. Supposed someone did not get their whole line dropped due to it being one day, regardless what the contract says. Not sure if that is true just what I heard.

I like Adlerdriver's answer because it's in WRITING ... isn't that a better answer than Contract Administration by rumor mill ("someone cousin's brother told me")?

You just need to watch the start times of you sim and reserve period, R24 will always require 2 days.

Actually C.E. told me personally and I think USMCFDX has hit on the reason why.

It basically has to be 2 days on either side, because the training has a 12 (I think) hour buffer with it on either side. Lets say you have a block of Rdays that ends with an Rday on Friday- you bid for training that goes Wednesday and Thursday so you think you're winning. But the training buffer removes the last Rday so you're not truly splitting the block. I know because it's happened to me many times.

I think leaving two days on either side is just being safe. It really only has to be one day left, but it's easy to screw it up, depending upon your reserve period. People don't think about when the reserve period ends or starts, and putting in the 12 hour buffer. It definitely requires some more careful thinking, but I am dead sure that if you account for when your reserve period actually starts or ends, add that 12 hour buffer, and if you do it correctly and there is one day on either side, it drops the entire block.

However, it is easy to screw up if you don't think carefully about it. Particularly if you have an R24 period.