In your situation it's very possible, and probably a good idea. If you can't get your kratom to match at the very least or exceed the strength of 350mgs of tramadol you may wanna look into a new supplier, especially if your not even using tramadol daily. I frequently use the both and 7.5g of decent quality kratom is, for me, definitely stronger than 300mgs of tramadol, and when my kratom use was at it's peak, 10g of kratom would still get me high whereas anything under 400mgs of tramadol was worthless, which meant I ended up dropping tramadol altogether.
Try upping your dose by a gram each time you use and if you don't find any beneficial effects look into a new supplier. Only buy kratom from online vendors who specialize in kratom and/or ethnobotanicals...
never buy brand name, packaged kratom and never buy your kratom from headshops.
1. No, kratom is a mu agonist like all opioids so as long as your using it, tolerance to "real" (kratom is just as much an opioid as tramadol) opioids won't decrease and will do just the opposite, increase tolerance. Good thing is tolerance to kratom generally builds very slowly for the majority of users.
2. Depends on how close you wanna cut it. A guaranteed problem free schedule would 2-3x a week with two days between doses, but you could typically get away with more if your a risk taker. As for tolerance, it depends on how quickly you build tolerance, therefor your gonna have to be the judge. If you start to notice the effects getting noticeably weaker, take a break. Due to it's incredibly short half-life tolerance drops FAST... faster than any other opioid I've tried.
3. Eh, hard to say because it's entirely dependent on the batch. Just today I received a new, very potent batch of bali that got me really buzzed. I say this with surprise as the batch of white vein borneo I went through before this barely did shit, and increasing the dose made me pretty sick. As this phenomenon is common with increasing tolerance, I just thought it was time for a break... turns out the batch just wasn't cutting it. Like I said, just work your way up and if you don't get a satisfying buzz get a new batch and try again. There's no reason you shouldn't be able to match the effects of such average doses of opioids as weak as tramadol. Unlike tramadol ime, stomach contents drastically affect how much you will get out of your dose. Try to eat your kratom on a near empty stomach. You can go for the completely empty stomach, but this isn't really necessary and can lead to some serious nausea if your stomach is so empty that your significantly hungry.
4. Nope, not really... and any benefit would be pretty miniscule bordering on placebo (besides additive effects in the case of psychoactives). Some will say to chug fresh grapefruit juice or eat enzyme inhibitors but that shit has just flat out never worked with kratom for me, or anyone I know for that matter. In fact taking enzyme inhibitors such as Cimetidintle (Tagamet) have only ever made for a significantly weaker, but longer lasting high which doesn't sound very beneficial in your scenario. You can experiment, but don't expect miracles. I would wait until you have tried upping the dose and/or trying another batch before dipping into these potentiators though.
You can try taking benedryl (Diphenhydramine) to potentiate your kratom, some swear by this but IME it just dulls the buzz and increases sedation. I'm in it for the euphoria, not sleepyness. What good is a nod if it's without euphoria? Cannabis goes fantastically with kratom, but it's definitely more of a synergy than potentiation. Good news is, If those doses of tramadol get you high, you won't need any potentiation. However, one thing you will notice is kratom doesn't last nearly as long as tramadol. With kratom I get on average a 3-4 hour buzz whereas Tramadol typically lasts around 7 or so hours.
Good luck in your search for a substitute
.