I use a 36 inch wide by 10 foot long ANCIENT National dryer and do WB and discharge just fine...
It does require the slowest belt speed which makes for around a 1 min 30 sec dwell, and it has beastly forced air, but it works just fine. I see my shirts in the wild a lot because I print for my wife's teacher friends and have loyal clients who have been reordering for years, and she and I wear shirts I have printed and cured in this dryer almost every day as well. I have 5+ year old DC shirts with bright reds, whites, yellows, etc that when held up to unwashed samples from the same run are basically indistinguishable except for the shirt fuzzing up over time like it does regardless of ink type. To be clear, the print itself is still bright and solid, but the fabric is "aged".
I couldn't print quickly on an auto with it, but as a manual printer it outpaces me just fine even on huge 21x15 full coverage prints.