heyboer seem to be quite good too at a lower price.
if i build an amp i would really consider the sozo cap too
check for PEC (mil spec) pot, these should be good(but really expensive).
i would also set some sprague capacitor on the board(bias supplie cap etc)
and the preamp a F&T with CarbonComp resistor. and maby set better powertube socket.
If you make it this way, please make a clip
, i plant on building something similar soon.
the metroamp instruction is something good to get.
and with MM trannies your sure it be right.
as for the tip, read well around amp building forum, there alot of info
and take care as there is really high voltage involved into building tubeamp.