I was in Res EW for 5 years in the mid 90's. In that time, we probably had about a dozen reg force pers "retire" into the reserves and start to parade with us. Only a couple of them lasted more than a year. Whatever they were looking for after their time in the regs, they didn't find it with us. (The ones that did last were huge assets to the squadron.)
Populating a knowledgable core of the R291 trade with ex-reg force pers sounds like a very dubious strategy to me. There will definitely be some attrition, and it might be to catastrophic levels. It's pretty hard to hold your core together when more than half of your team walks out.
As for the length of training, experience with POET shows that it is exceedingly difficult to get a reservist on a year long training course. By necessity, the R291 QL3 will be shorter, more concentrated, and miss many PO's that are on the reg force course. Reservists in the sigs and int worlds have to focus on smaller parts of the trade to be effective. R215 concentrates on combat net radio, while their counterparts in the regt play a lot more with microwave, satellite, etc. R111 similarly ignores many aspects of the trade that 111's have more time to work on.
R291 training will be similarly focused. If not, the only people in the trade will be reg force retirees, and reservists who wish to work class B for the rest of their career. This is a very small pool of people to draw on, and I don't think it would make for a healthy trade.
