I’m trying to increases the visible length of the glass in the water level gauge on my vertical boiler. I obviously can’t move the bosses in the boiler. I seem to remember Peter Rich used to advocate end sealed glass. Anyone know where I can find the drawings? Anyone got real experience of them? My main worry is that with 32 tpi bosses I can’t guarantee better than +- 1/64” alignment between top and bottom fitting. Does this matter, or is there some trick to getting it better?