How big of a seizure risk is it really if you're a) an occasional user of tramadol b) not prone to seizures? Personally I always wait atleast one week between using tramadol, often much longer. When I do take them though, I never take less than 300mg, it would be a waste in my book (recretionally). Staggering the dose is a good idea too in my opinion, if I want to take 450mg total I'd take 75mg every 30 minutes until it's all consumed (maybe 150mg as a starter dose and 75mg every 30mins after that). ER formulations of tramadol seem to last aeons so it's nice to take small amounts at small intervals until I reach a comfortable level of stimulation, the sedation will catch up sooner or later.
I'm not that much of a fan of opiates luckily anyway, but tramadol is an exception in my book. I like it much more than say, oxycodone. Sometimes I take a low dose of clonazepam (0,5mg) to combat the risk of seizure, but I'm not sure if that's necessary for me (or even helping).