Alex,
*sigh* you are right. I was too hasty in comparing the PSXX to a 3 Amp booster in terms of price. The PSXX-3's I have cost around the same price as a single YD7403. So 3 times as much per protected area.
At the moment I have a DCS240 with an 8 Amp power supply feeding the lower level and that is divided into 6 circuit breaker zones using a couple of PSXX-3's.
I've been buying or going on wait lists to covert to the YaMoRC / Digikeijs universe and trying to figure out what gets removed or replaced on the layout. That's why I was asking about circuit breakers. It's a fairly steep price to pay to use start using Railcom but that's my decision - cost being secondary to functionality and fun. Do I need Railcom? Of course not, but do I want it? Yes :)
I don't use Keep Alives or PowerPacks so that's not a factor in my case. It was the main reason the PSX was replaced by the PSXX if I read the blogs correctly.
What I am seeing here though is an answer to my initial question. It has become a discussion about the number of boosters needed to do the job. However, I do intend to have a lot of trains running at one time with iTrain. My UWT-100 will keep me busy running the 'local', switchers and manifests while the unit trains keep the mainlines busy. A visitor can use a phone or my DT602d. When product from YaMoRC becomes available I believe I will be completing the transition without PSXXs or EB-1s. I will try to limit my use of boosters, but I will be using them to isolate areas of the layout irrespective of how many Amps are needed.
Oldngrey