@blkwrxwgn I bought my SLP-05 used and it came with the stock EH tubes. Maybe they were worn out but I really disliked them. Actually thought about selling the SLP-05 until I changed them out.
It has never been clear to me if you need to have a matched quad in 1,2,4,5 or if you can have one type in 1,4 and another type in 2,5. It sounds like you had good results mixing them?