They will work okay together, it's really just a waste to combine them. If you want safety it should be something like deca and primo, and if you want fast results you want tren and and a compound that's not nor-test based. When I say they will work okay together, I mean 375mg a week of tren and 200 mg a week of deca might bring better results than 575mg a week of deca (that number's just for example) but there's just really not much point in stacking the two in most people's opinions.
But then again, I can see a guy saying he wants the benefits of tren but he wants some deca for joint benefits and isn't scared of "deca dick". As far as suppression, if we're talking HPTA suppression I hate to tell all these test freaks but TEST is in fact much more suppressive than deca. Even 200-400mg of test weekly causes near 100% suppression of natural test within a month or so. Deca simply gets it's reputation for suppression from the fact that it reduces natural test while not supplying any exogenous test.
Long and short of it though is that it's not an ideal stack as there are much better combinations for almost any purpose intended. IOW, this is not the stack to "order" but if you already have it lying around you are not a nut for doing it.