Can I ask should I increase Thiamin (should it be a particular kind?) if I'm taking high-dose Biotin
I don't know of any direct connection whereby increased biotin would create an increased need for thiamine. I did a quite Google and did find a rare inborn error of metabolism which affects a thiamine transporter. The disorder responds to high dose biotin. I tried to find out more about the mechanism but couldn't.
There could be an indirect link in that both cofactors are critical in energy pathways. If high dose biotin were stimulating these, this might increase demand for thiamine.
I haven't experimented much with thiamine. When I decided to stop taking a B complex and try varying amounts of the individual components (mainly because of oxalates and B12/folate), I just followed Susan Owen's recommendation's re oxalates.
She favours allithiamine, a fat soluble form which crosses the BBB. The fat soluble properties mean it is released more slowly that water soluble forms and makes it hang around longer.
I have just taken 1 x 50 mg daily.
It could be worth experimenting with but there have always been more pressing things for me and I haven't got around to it.
will Biotin increase need for potassium
I haven't found this myself but I imagine there could be individual variation.