micke,
Ouch! You're not making this easy...
First, you might want to rename this as an Aleph 3, instead of an Aleph 5.
An Aleph 3 has 2 pairs of output devices, which you've already done. It has a rail of +-25V, which you've already done. What remains is to change some part values. Fetch the Aleph 3 schematics, and we'll use those part numbers.
-First compare parts values here and there. Change to Aleph 3 values in all cases *except* R113.
-R113 will set your bias current. Use the Aleph 3 value of .47 ohms for R120-123, but *decrease* the value of R113. The value shown on the Aleph 3 schematic is 47k. Start coming down off of that value until you reach a measured voltage across R120-123 of approximately .25-.3V. This will put you in the vicinity of 60W dissipation per channel. We are assuming that you are confident that your heatsinks will safely dissipate 60W/channel (and assuming that all output devices per channel are mounted on the same heatsink) as you said above. You may need to adjust R113 further, depending on how much heat you can deal with.
-Assuming that I'm scratching this out correctly (this is just me and my trusty pocket calculator--no warranty expressed or implied--your mileage may vary), you'll end up with about 11-12W output into an 8ohm load, or about the same as a Zen, albeit with a more sophisticated circuit. The amp will swing approximately 15-16V, but will current limit before it gets to express its full power.
Good luck.
Grey