To add my 2cents.
No experience with ergoline-containing seeds, but as has been said in previous posts it's easy to get in over your head when doing MXE+Psychedelics.
While me and acquaintances would regularly use MXE, and at minimal doses of say ~30mg, just for the casual fucked-upness of mex, 20-30mg dosed to coincide with the plateau/tapering off of effects of ~20mg 4-HO-MiPT was absolutely overwhelming. I've had one friend straight-up wig out and have to be looked after by his girlfriend in a very low-key setting, not entirely incapacitated physically but mentally just buttfucked.
Another friend went from a completely manageable trip to lost in his own world, not like he literally 'wasn't there', but like a child, his concept of what was going on seemed significantly more fantastic and mind-boggled, yet he could barely communicate his feelings and i could tell this quickly became quite frustrating if not frightening for him. That was only 20mg as well, and this is someone who would likely have laughed at a 20mg dose of MXE at the time, and WAS laughing at a 20mg dose of Miprocin.
Staggered doses of 5-15mg MXE/aMT over the course of a couple of hours (reaching approx 120mg MXE and 80mg aMT) provided the most euphoric, hedonistic night of my life. Felt the definition of 'fried' the morning after but nothing too unpleasant compared to heavy boozing/stimulant post-effects.
Personally, i would not dose more than 20mg at once when tripping, just because it does seem to be a gamble between induced dysphoria/euphoria, leaning towards dysphoric the higher the dose of MXE.
The 'safest' time to dose i think would be after the peak, just remember the longer you leave it the less enhanced the MXE high will be. Also they potentiate the FUCK out of each other.
I wish you the best on this voyage!