Hi mate
nice one getting them fitted so quick!
Ah yeah I found getting the spade connector into the back of the fuse box and the fuse to go into them via the front so fiddly, pretty much due to not being able to move the fuse box out much for better access.
Good to hear the piggyback fuse holders are good for 30a, cheers for finding out about that. Much much easier to do it that way
And to answer your question, yes the drivers and passengers seat will both be permanent live using my set up as the power feed is taken from the fuse box behind the glove box. This won't drain any power as the motors dont use power unless the seats are being moved, but comes in handy when cleaning around the car when you don't have the key turned in the ignition
The heated seats however turn off as soon as the key is taken out of the ignition, so they wont drain your battery
If you want the power to be ignition live, I guess it would just be a matter of taking power from two empty slots on the ignition in the steering column, I believe pins 3, 7 and 10 are empty