Thanks everyone for the feedback. Although I'm entering my 3rd year for this stuff, I still consider myself to be pretty much a newbie in the game. I did do my own build of two of the d-light silver edition boards, and the reason I raised this question is that the d-light board is rated for up to 8 amps on a channel when using the heavy duty heatsinks.
I also understand Keith's post about 96 amps, so before anything gets plugged, every channels amp draw is measured with the P3 Kill-a-watt, then the values are loaded into a spreadsheet and my channels calculated to balance draw across the boards. In fact, my draw per 8 channels is actually lower this year than it was last year, this is because I added 16 more channels and was able to switch out some of my incandescent strings to LED's.
From a design perspective, it appears that yes this triac can be substituted as a mod to the express, however one must still be mindful of the total amp draw on the bank of 8 and not exceed 16 amps (80% of your 20 amp circuit)
This mod would allow for 1 or 2 channels of a higher amp draw (e.g. 5 amps) and 6 or 7 of low draw (e.g. 1 amp or less)
-Curt