And to answer your question, I think ~ 500-520 TSS is reasonable at 10 hrs per week. You'd not have to go below ~-30 TSB.

Mon - 3x20's, 90 min total (warm up/cool down/recoveries) (100 TSS)
Tues - 2x20's, 60 min total (80 TSS)
Wed - ~75 min (50 TSS)
Thur - Threshold workout of choice, 90 min total, (~100 TSS)
Fri - Recovery, 60 min, (25 TSS)
Sat - 3 hrs endurance, (170 TSS)
Sun - Off

Ramped at 8, 8, 6, 6 in the first four weeks, but that's really just reseeding your actual fitness. Ramp at 5 or less from there.

YMMV, and certainly depends on what you're training when. I'm no coach and can't claim that the above workout would work for anyone - even me!